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diff --git a/Documentation/scsi/ibmmca.txt b/Documentation/scsi/ibmmca.txt deleted file mode 100644 index ac41a9fcac77..000000000000 --- a/Documentation/scsi/ibmmca.txt +++ /dev/null @@ -1,1402 +0,0 @@ - - -=< The IBM Microchannel SCSI-Subsystem >=- - - for the IBM PS/2 series - - Low Level Software-Driver for Linux - - Copyright (c) 1995 Strom Systems, Inc. under the terms of the GNU - General Public License. Originally written by Martin Kolinek, December 1995. - Officially modified and maintained by Michael Lang since January 1999. - - Version 4.0a - - Last update: January 3, 2001 - - Before you Start - ---------------- - This is the common README.ibmmca file for all driver releases of the - IBM MCA SCSI driver for Linux. Please note, that driver releases 4.0 - or newer do not work with kernel versions older than 2.4.0, while driver - versions older than 4.0 do not work with kernels 2.4.0 or later! If you - try to compile your kernel with the wrong driver source, the - compilation is aborted and you get a corresponding error message. This is - no bug in the driver; it prevents you from using the wrong source code - with the wrong kernel version. - - Authors of this Driver - ---------------------- - - Chris Beauregard (improvement of the SCSI-device mapping by the driver) - - Martin Kolinek (origin, first release of this driver) - - Klaus Kudielka (multiple SCSI-host management/detection, adaption to - Linux Kernel 2.1.x, module support) - - Michael Lang (assigning original pun/lun mapping, dynamical ldn - assignment, rewritten adapter detection, this file, - patches, official driver maintenance and subsequent - debugging, related with the driver) - - Table of Contents - ----------------- - 1 Abstract - 2 Driver Description - 2.1 IBM SCSI-Subsystem Detection - 2.2 Physical Units, Logical Units, and Logical Devices - 2.3 SCSI-Device Recognition and dynamical ldn Assignment - 2.4 SCSI-Device Order - 2.5 Regular SCSI-Command-Processing - 2.6 Abort & Reset Commands - 2.7 Disk Geometry - 2.8 Kernel Boot Option - 2.9 Driver Module Support - 2.10 Multiple Hostadapter Support - 2.11 /proc/scsi-Filesystem Information - 2.12 /proc/mca-Filesystem Information - 2.13 Supported IBM SCSI-Subsystems - 2.14 Linux Kernel Versions - 3 Code History - 4 To do - 5 Users' Manual - 5.1 Commandline Parameters - 5.2 Troubleshooting - 5.3 Bug reports - 5.4 Support WWW-page - 6 References - 7 Credits to - 7.1 People - 7.2 Sponsors & Supporters - 8 Trademarks - 9 Disclaimer - - * * * - - 1 Abstract - ---------- - This README-file describes the IBM SCSI-subsystem low level driver for - Linux. The descriptions which were formerly kept in the source code have - been taken out of this file to simplify the codes readability. The driver - description has been updated, as most of the former description was already - quite outdated. The history of the driver development is also kept inside - here. Multiple historical developments have been summarized to shorten the - text size a bit. At the end of this file you can find a small manual for - this driver and hints to get it running on your machine. - - 2 Driver Description - -------------------- - 2.1 IBM SCSI-Subsystem Detection - -------------------------------- - This is done in the ibmmca_detect() function. It first checks, if the - Microchannel-bus support is enabled, as the IBM SCSI-subsystem needs the - Microchannel. In a next step, a free interrupt is chosen and the main - interrupt handler is connected to it to handle answers of the SCSI- - subsystem(s). If the F/W SCSI-adapter is forced by the BIOS to use IRQ11 - instead of IRQ14, IRQ11 is used for the IBM SCSI-2 F/W adapter. In a - further step it is checked, if the adapter gets detected by force from - the kernel commandline, where the I/O port and the SCSI-subsystem id can - be specified. The next step checks if there is an integrated SCSI-subsystem - installed. This register area is fixed through all IBM PS/2 MCA-machines - and appears as something like a virtual slot 10 of the MCA-bus. On most - PS/2 machines, the POS registers of slot 10 are set to 0xff or 0x00 if not - integrated SCSI-controller is available. But on certain PS/2s, like model - 9595, this slot 10 is used to store other information which at earlier - stage confused the driver and resulted in the detection of some ghost-SCSI. - If POS-register 2 and 3 are not 0x00 and not 0xff, but all other POS - registers are either 0xff or 0x00, there must be an integrated SCSI- - subsystem present and it will be registered as IBM Integrated SCSI- - Subsystem. The next step checks, if there is a slot-adapter installed on - the MCA-bus. To get this, the first two POS-registers, that represent the - adapter ID are checked. If they fit to one of the ids, stored in the - adapter list, a SCSI-subsystem is assumed to be found in a slot and will be - registered. This check is done through all possible MCA-bus slots to allow - more than one SCSI-adapter to be present in the PS/2-system and this is - already the first point of problems. Looking into the technical reference - manual for the IBM PS/2 common interfaces, the POS2 register must have - different interpretation of its single bits to avoid overlapping I/O - regions. While one can assume, that the integrated subsystem has a fix - I/O-address at 0x3540 - 0x3547, further installed IBM SCSI-adapters must - use a different I/O-address. This is expressed by bit 1 to 3 of POS2 - (multiplied by 8 + 0x3540). Bits 2 and 3 are reserved for the integrated - subsystem, but not for the adapters! The following list shows, how the - bits of POS2 and POS3 should be interpreted. - - The POS2-register of all PS/2 models' integrated SCSI-subsystems has the - following interpretation of bits: - Bit 7 - 4 : Chip Revision ID (Release) - Bit 3 - 2 : Reserved - Bit 1 : 8k NVRAM Disabled - Bit 0 : Chip Enable (EN-Signal) - The POS3-register is interpreted as follows (for most IBM SCSI-subsys.): - Bit 7 - 5 : SCSI ID - Bit 4 - 0 : Reserved = 0 - The slot-adapters have different interpretation of these bits. The IBM SCSI - adapter (w/Cache) and the IBM SCSI-2 F/W adapter use the following - interpretation of the POS2 register: - Bit 7 - 4 : ROM Segment Address Select - Bit 3 - 1 : Adapter I/O Address Select (*8+0x3540) - Bit 0 : Adapter Enable (EN-Signal) - and for the POS3 register: - Bit 7 - 5 : SCSI ID - Bit 4 : Fairness Enable (SCSI ID3 f. F/W) - Bit 3 - 0 : Arbitration Level - The most modern product of the series is the IBM SCSI-2 F/W adapter, it - allows dual-bus SCSI and SCSI-wide addressing, which means, PUNs may be - between 0 and 15. Here, Bit 4 is the high-order bit of the 4-bit wide - adapter PUN expression. In short words, this means, that IBM PS/2 machines - can only support 1 single integrated subsystem by default. Additional - slot-adapters get ports assigned by the automatic configuration tool. - - One day I found a patch in ibmmca_detect(), forcing the I/O-address to be - 0x3540 for integrated SCSI-subsystems, there was a remark placed, that on - integrated IBM SCSI-subsystems of model 56, the POS2 register was showing 5. - This means, that really for these models, POS2 has to be interpreted - sticking to the technical reference guide. In this case, the bit 2 (4) is - a reserved bit and may not be interpreted. These differences between the - adapters and the integrated controllers are taken into account by the - detection routine of the driver on from version >3.0g. - - Every time, a SCSI-subsystem is discovered, the ibmmca_register() function - is called. This function checks first, if the requested area for the I/O- - address of this SCSI-subsystem is still available and assigns this I/O- - area to the SCSI-subsystem. There are always 8 sequential I/O-addresses - taken for each individual SCSI-subsystem found, which are: - - Offset Type Permissions - 0 Command Interface Register 1 Read/Write - 1 Command Interface Register 2 Read/Write - 2 Command Interface Register 3 Read/Write - 3 Command Interface Register 4 Read/Write - 4 Attention Register Read/Write - 5 Basic Control Register Read/Write - 6 Interrupt Status Register Read - 7 Basic Status Register Read - - After the I/O-address range is assigned, the host-adapter is assigned - to a local structure which keeps all adapter information needed for the - driver itself and the mid- and higher-level SCSI-drivers. The SCSI pun/lun - and the adapters' ldn tables are initialized and get probed afterwards by - the check_devices() function. If no further adapters are found, - ibmmca_detect() quits. - - 2.2 Physical Units, Logical Units, and Logical Devices - ------------------------------------------------------ - There can be up to 56 devices on the SCSI bus (besides the adapter): - there are up to 7 "physical units" (each identified by physical unit - number or pun, also called the scsi id, this is the number you select - with hardware jumpers), and each physical unit can have up to 8 - "logical units" (each identified by logical unit number, or lun, - between 0 and 7). The IBM SCSI-2 F/W adapter offers this on up to two - busses and provides support for 30 logical devices at the same time, where - in wide-addressing mode you can have 16 puns with 32 luns on each device. - This section describes the handling of devices on non-F/W adapters. - Just imagine, that you can have 16 * 32 = 512 devices on a F/W adapter - which means a lot of possible devices for such a small machine. - - Typically the adapter has pun=7, so puns of other physical units - are between 0 and 6(15). On a wide-adapter a pun higher than 7 is - possible, but is normally not used. Almost all physical units have only - one logical unit, with lun=0. A CD-ROM jukebox would be an example of a - physical unit with more than one logical unit. - - The embedded microprocessor of the IBM SCSI-subsystem hides the complex - two-dimensional (pun,lun) organization from the operating system. - When the machine is powered-up (or rebooted), the embedded microprocessor - checks, on its own, all 56 possible (pun,lun) combinations, and the first - 15 devices found are assigned into a one-dimensional array of so-called - "logical devices", identified by "logical device numbers" or ldn. The last - ldn=15 is reserved for the subsystem itself. Wide adapters may have - to check up to 15 * 8 = 120 pun/lun combinations. - - 2.3 SCSI-Device Recognition and Dynamical ldn Assignment - -------------------------------------------------------- - One consequence of information hiding is that the real (pun,lun) - numbers are also hidden. The two possibilities to get around this problem - are to offer fake pun/lun combinations to the operating system or to - delete the whole mapping of the adapter and to reassign the ldns, using - the immediate assign command of the SCSI-subsystem for probing through - all possible pun/lun combinations. An ldn is a "logical device number" - which is used by IBM SCSI-subsystems to access some valid SCSI-device. - At the beginning of the development of this driver, the following approach - was used: - - First, the driver checked the ldn's (0 to 6) to find out which ldn's - have devices assigned. This was done by the functions check_devices() and - device_exists(). The interrupt handler has a special paragraph of code - (see local_checking_phase_flag) to assist in the checking. Assume, for - example, that three logical devices were found assigned at ldn 0, 1, 2. - These are presented to the upper layer of Linux SCSI driver - as devices with bogus (pun, lun) equal to (0,0), (1,0), (2,0). - On the other hand, if the upper layer issues a command to device - say (4,0), this driver returns DID_NO_CONNECT error. - - In a second step of the driver development, the following improvement has - been applied: The first approach limited the number of devices to 7, far - fewer than the 15 that it could use, then it just mapped ldn -> - (ldn/8,ldn%8) for pun,lun. We ended up with a real mishmash of puns - and luns, but it all seemed to work. - - The latest development, which is implemented from the driver version 3.0 - and later, realizes the device recognition in the following way: - The physical SCSI-devices on the SCSI-bus are probed via immediate_assign- - and device_inquiry-commands, that is all implemented in a completely new - made check_devices() subroutine. This delivers an exact map of the physical - SCSI-world that is now stored in the get_scsi[][]-array. This means, - that the once hidden pun,lun assignment is now known to this driver. - It no longer believes in default-settings of the subsystem and maps all - ldns to existing pun,lun "by foot". This assures full control of the ldn - mapping and allows dynamical remapping of ldns to different pun,lun, if - there are more SCSI-devices installed than ldns available (n>15). The - ldns from 0 to 6 get 'hardwired' by this driver to puns 0 to 7 at lun=0, - excluding the pun of the subsystem. This assures, that at least simple - SCSI-installations have optimum access-speed and are not touched by - dynamical remapping. The ldns 7 to 14 are put to existing devices with - lun>0 or to non-existing devices, in order to satisfy the subsystem, if - there are less than 15 SCSI-devices connected. In the case of more than 15 - devices, the dynamical mapping goes active. If the get_scsi[][] reports a - device to be existent, but it has no ldn assigned, it gets an ldn out of 7 - to 14. The numbers are assigned in cyclic order, therefore it takes 8 - dynamical reassignments on the SCSI-devices until a certain device - loses its ldn again. This assures that dynamical remapping is avoided - during intense I/O between up to 15 SCSI-devices (means pun,lun - combinations). A further advantage of this method is that people who - build their kernel without probing on all luns will get what they expect, - because the driver just won't assign everything with lun>0 when - multiple lun probing is inactive. - - 2.4 SCSI-Device Order - --------------------- - Because of the now correct recognition of physical pun,lun, and - their report to mid-level- and higher-level-drivers, the new reported puns - can be different from the old, faked puns. Therefore, Linux will eventually - change /dev/sdXXX assignments and prompt you for corrupted superblock - repair on boottime. In this case DO NOT PANIC, YOUR DISKS ARE STILL OK!!! - You have to reboot (CTRL-D) with an old kernel and set the /etc/fstab-file - entries right. After that, the system should come up as errorfree as before. - If your boot-partition is not coming up, also edit the /etc/lilo.conf-file - in a Linux session booted on old kernel and run lilo before reboot. Check - lilo.conf anyway to get boot on other partitions with foreign OSes right - again. But there exists a feature of this driver that allows you to change - the assignment order of the SCSI-devices by flipping the PUN-assignment. - See the next paragraph for a description. - - The problem for this is, that Linux does not assign the SCSI-devices in the - way as described in the ANSI-SCSI-standard. Linux assigns /dev/sda to - the device with at minimum id 0. But the first drive should be at id 6, - because for historical reasons, drive at id 6 has, by hardware, the highest - priority and a drive at id 0 the lowest. IBM was one of the rare producers, - where the BIOS assigns drives belonging to the ANSI-SCSI-standard. Most - other producers' BIOS does not (I think even Adaptec-BIOS). The - IBMMCA_SCSI_ORDER_STANDARD flag, which you set while configuring the - kernel enables to choose the preferred way of SCSI-device-assignment. - Defining this flag would result in Linux determining the devices in the - same order as DOS and OS/2 does on your MCA-machine. This is also standard - on most industrial computers and OSes, like e.g. OS-9. Leaving this flag - undefined will get your devices ordered in the default way of Linux. See - also the remarks of Chris Beauregard from Dec 15, 1997 and the followups - in section 3. - - 2.5 Regular SCSI-Command-Processing - ----------------------------------- - Only three functions get involved: ibmmca_queuecommand(), issue_cmd(), - and interrupt_handler(). - - The upper layer issues a scsi command by calling function - ibmmca_queuecommand(). This function fills a "subsystem control block" - (scb) and calls a local function issue_cmd(), which writes a scb - command into subsystem I/O ports. Once the scb command is carried out, - the interrupt_handler() is invoked. If a device is determined to be - existent and it has not assigned any ldn, it gets one dynamically. - For this, the whole stuff is done in ibmmca_queuecommand(). - - 2.6 Abort & Reset Commands - -------------------------- - These are implemented with busy waiting for interrupt to arrive. - ibmmca_reset() and ibmmca_abort() do not work sufficiently well - up to now and need still a lot of development work. This seems - to be a problem with other low-level SCSI drivers too, however - this should be no excuse. - - 2.7 Disk Geometry - ----------------- - The ibmmca_biosparams() function should return the same disk geometry - as the bios. This is needed for fdisk, etc. The returned geometry is - certainly correct for disks smaller than 1 gigabyte. In the meantime, - it has been proved, that this works fine even with disks larger than - 1 gigabyte. - - 2.8 Kernel Boot Option - ---------------------- - The function ibmmca_scsi_setup() is called if option ibmmcascsi=n - is passed to the kernel. See file linux/init/main.c for details. - - 2.9 Driver Module Support - ------------------------- - Is implemented and tested by K. Kudielka. This could probably not work - on kernels <2.1.0. - - 2.10 Multiple Hostadapter Support - --------------------------------- - This driver supports up to eight interfaces of type IBM-SCSI-Subsystem. - Integrated-, and MCA-adapters are automatically recognized. Unrecognizable - IBM-SCSI-Subsystem interfaces can be specified as kernel-parameters. - - 2.11 /proc/scsi-Filesystem Information - -------------------------------------- - Information about the driver condition is given in - /proc/scsi/ibmmca/<host_no>. ibmmca_proc_info() provides this information. - - This table is quite informative for interested users. It shows the load - of commands on the subsystem and whether you are running the bypassed - (software) or integrated (hardware) SCSI-command set (see below). The - amount of accesses is shown. Read, write, modeselect is shown separately - in order to help debugging problems with CD-ROMs or tapedrives. - - The following table shows the list of 15 logical device numbers, that are - used by the SCSI-subsystem. The load on each ldn is shown in the table, - again, read and write commands are split. The last column shows the amount - of reassignments, that have been applied to the ldns, if you have more than - 15 pun/lun combinations available on the SCSI-bus. - - The last two tables show the pun/lun map and the positions of the ldns - on this pun/lun map. This may change during operation, when a ldn is - reassigned to another pun/lun combination. If the necessity for dynamical - assignments is set to 'no', the ldn structure keeps static. - - 2.12 /proc/mca-Filesystem Information - ------------------------------------- - The slot-file contains all default entries and in addition chip and I/O- - address information of the SCSI-subsystem. This information is provided - by ibmmca_getinfo(). - - 2.13 Supported IBM SCSI-Subsystems - ---------------------------------- - The following IBM SCSI-subsystems are supported by this driver: - - - IBM Fast/Wide SCSI-2 Adapter - - IBM 7568 Industrial Computer SCSI Adapter w/Cache - - IBM Expansion Unit SCSI Controller - - IBM SCSI Adapter w/Cache - - IBM SCSI Adapter - - IBM Integrated SCSI Controller - - All clones, 100% compatible with the chipset and subsystem command - system of IBM SCSI-adapters (forced detection) - - 2.14 Linux Kernel Versions - -------------------------- - The IBM SCSI-subsystem low level driver is prepared to be used with - all versions of Linux between 2.0.x and 2.4.x. The compatibility checks - are fully implemented up from version 3.1e of the driver. This means, that - you just need the latest ibmmca.h and ibmmca.c file and copy it in the - linux/drivers/scsi directory. The code is automatically adapted during - kernel compilation. This is different from kernel 2.4.0! Here version - 4.0 or later of the driver must be used for kernel 2.4.0 or later. Version - 4.0 or later does not work together with older kernels! Driver versions - older than 4.0 do not work together with kernel 2.4.0 or later. They work - on all older kernels. - - 3 Code History - -------------- - Jan 15 1996: First public release. - - Martin Kolinek - - Jan 23 1996: Scrapped code which reassigned scsi devices to logical - device numbers. Instead, the existing assignment (created - when the machine is powered-up or rebooted) is used. - A side effect is that the upper layer of Linux SCSI - device driver gets bogus scsi ids (this is benign), - and also the hard disks are ordered under Linux the - same way as they are under dos (i.e., C: disk is sda, - D: disk is sdb, etc.). - - Martin Kolinek - - I think that the CD-ROM is now detected only if a CD is - inside CD_ROM while Linux boots. This can be fixed later, - once the driver works on all types of PS/2's. - - Martin Kolinek - - Feb 7 1996: Modified biosparam function. Fixed the CD-ROM detection. - For now, devices other than harddisk and CD_ROM are - ignored. Temporarily modified abort() function - to behave like reset(). - - Martin Kolinek - - Mar 31 1996: The integrated scsi subsystem is correctly found - in PS/2 models 56,57, but not in model 76. Therefore - the ibmmca_scsi_setup() function has been added today. - This function allows the user to force detection of - scsi subsystem. The kernel option has format - ibmmcascsi=n - where n is the scsi_id (pun) of the subsystem. Most likely, n is 7. - - Martin Kolinek - - Aug 21 1996: Modified the code which maps ldns to (pun,0). It was - insufficient for those of us with CD-ROM changers. - - Chris Beauregard - - Dec 14 1996: More improvements to the ldn mapping. See check_devices - for details. Did more fiddling with the integrated SCSI detection, - but I think it's ultimately hopeless without actually testing the - model of the machine. The 56, 57, 76 and 95 (ultimedia) all have - different integrated SCSI register configurations. However, the 56 - and 57 are the only ones that have problems with forced detection. - - Chris Beauregard - - Mar 8-16 1997: Modified driver to run as a module and to support - multiple adapters. A structure, called ibmmca_hostdata, is now - present, containing all the variables, that were once only - available for one single adapter. The find_subsystem-routine has vanished. - The hardware recognition is now done in ibmmca_detect directly. - This routine checks for presence of MCA-bus, checks the interrupt - level and continues with checking the installed hardware. - Certain PS/2-models do not recognize a SCSI-subsystem automatically. - Hence, the setup defined by command-line-parameters is checked first. - Thereafter, the routine probes for an integrated SCSI-subsystem. - Finally, adapters are checked. This method has the advantage to cover all - possible combinations of multiple SCSI-subsystems on one MCA-board. Up to - eight SCSI-subsystems can be recognized and announced to the upper-level - drivers with this improvement. A set of defines made changes to other - routines as small as possible. - - Klaus Kudielka - - May 30 1997: (v1.5b) - 1) SCSI-command capability enlarged by the recognition of MODE_SELECT. - This needs the RD-Bit to be disabled on IM_OTHER_SCSI_CMD_CMD which - allows data to be written from the system to the device. It is a - necessary step to be allowed to set blocksize of SCSI-tape-drives and - the tape-speed, without confusing the SCSI-Subsystem. - 2) The recognition of a tape is included in the check_devices routine. - This is done by checking for TYPE_TAPE, that is already defined in - the kernel-scsi-environment. The markup of a tape is done in the - global ldn_is_tape[] array. If the entry on index ldn - is 1, there is a tapedrive connected. - 3) The ldn_is_tape[] array is necessary to distinguish between tape- and - other devices. Fixed blocklength devices should not cause a problem - with the SCB-command for read and write in the ibmmca_queuecommand - subroutine. Therefore, I only derivate the READ_XX, WRITE_XX for - the tape-devices, as recommended by IBM in this Technical Reference, - mentioned below. (IBM recommends to avoid using the read/write of the - subsystem, but the fact was, that read/write causes a command error from - the subsystem and this causes kernel-panic.) - 4) In addition, I propose to use the ldn instead of a fix char for the - display of PS2_DISK_LED_ON(). On 95, one can distinguish between the - devices that are accessed. It shows activity and easyfies debugging. - The tape-support has been tested with a SONY SDT-5200 and a HP DDS-2 - (I do not know yet the type). Optimization and CD-ROM audio-support, - I am working on ... - - Michael Lang - - June 19 1997: (v1.6b) - 1) Submitting the extra-array ldn_is_tape[] -> to the local ld[] - device-array. - 2) CD-ROM Audio-Play seems to work now. - 3) When using DDS-2 (120M) DAT-Tapes, mtst shows still density-code - 0x13 for ordinary DDS (61000 BPM) instead 0x24 for DDS-2. This appears - also on Adaptec 2940 adaptor in a PCI-System. Therefore, I assume that - the problem is independent of the low-level-driver/bus-architecture. - 4) Hexadecimal ldn on PS/2-95 LED-display. - 5) Fixing of the PS/2-LED on/off that it works right with tapedrives and - does not confuse the disk_rw_in_progress counter. - - Michael Lang - - June 21 1997: (v1.7b) - 1) Adding of a proc_info routine to inform in /proc/scsi/ibmmca/<host> the - outer-world about operational load statistics on the different ldns, - seen by the driver. Everybody that has more than one IBM-SCSI should - test this, because I only have one and cannot see what happens with more - than one IBM-SCSI hosts. - 2) Definition of a driver version-number to have a better recognition of - the source when there are existing too much releases that may confuse - the user, when reading about release-specific problems. Up to know, - I calculated the version-number to be 1.7. Because we are in BETA-test - yet, it is today 1.7b. - 3) Sorry for the heavy bug I programmed on June 19 1997! After that, the - CD-ROM did not work any more! The C7-command was a fake impression - I got while programming. Now, the READ and WRITE commands for CD-ROM are - no longer running over the subsystem, but just over - IM_OTHER_SCSI_CMD_CMD. On my observations (PS/2-95), now CD-ROM mounts - much faster(!) and hopefully all fancy multimedia-functions, like direct - digital recording from audio-CDs also work. (I tried it with cdda2wav - from the cdwtools-package and it filled up the harddisk immediately :-).) - To easify boolean logics, a further local device-type in ld[], called - is_cdrom has been included. - 4) If one uses a SCSI-device of unsupported type/commands, one - immediately runs into a kernel-panic caused by Command Error. To better - understand which SCSI-command caused the problem, I extended this - specific panic-message slightly. - - Michael Lang - - June 25 1997: (v1.8b) - 1) Some cosmetic changes for the handling of SCSI-device-types. - Now, also CD-Burners / WORMs and SCSI-scanners should work. For - MO-drives I have no experience, therefore not yet supported. - In logical_devices I changed from different type-variables to one - called 'device_type' where the values, corresponding to scsi.h, - of a SCSI-device are stored. - 2) There existed a small bug, that maps a device, coming after a SCSI-tape - wrong. Therefore, e.g. a CD-ROM changer would have been mapped wrong - -> problem removed. - 3) Extension of the logical_device structure. Now it contains also device, - vendor and revision-level of a SCSI-device for internal usage. - - Michael Lang - - June 26-29 1997: (v2.0b) - 1) The release number 2.0b is necessary because of the completely new done - recognition and handling of SCSI-devices with the adapter. As I got - from Chris the hint, that the subsystem can reassign ldns dynamically, - I remembered this immediate_assign-command, I found once in the handbook. - Now, the driver first kills all ldn assignments that are set by default - on the SCSI-subsystem. After that, it probes on all puns and luns for - devices by going through all combinations with immediate_assign and - probing for devices, using device_inquiry. The found physical(!) pun,lun - structure is stored in get_scsi[][] as device types. This is followed - by the assignment of all ldns to existing SCSI-devices. If more ldns - than devices are available, they are assigned to non existing pun,lun - combinations to satisfy the adapter. With this, the dynamical mapping - was possible to implement. (For further info see the text in the - source code and in the description below. Read the description - below BEFORE installing this driver on your system!) - 2) Changed the name IBMMCA_DRIVER_VERSION to IBMMCA_SCSI_DRIVER_VERSION. - 3) The LED-display shows on PS/2-95 no longer the ldn, but the SCSI-ID - (pun) of the accessed SCSI-device. This is now senseful, because the - pun known within the driver is exactly the pun of the physical device - and no longer a fake one. - 4) The /proc/scsi/ibmmca/<host_no> consists now of the first part, where - hit-statistics of ldns is shown and a second part, where the maps of - physical and logical SCSI-devices are displayed. This could be very - interesting, when one is using more than 15 SCSI-devices in order to - follow the dynamical remapping of ldns. - - Michael Lang - - June 26-29 1997: (v2.0b-1) - 1) I forgot to switch the local_checking_phase_flag to 1 and back to 0 - in the dynamical remapping part in ibmmca_queuecommand for the - device_exist routine. Sorry. - - Michael Lang - - July 1-13 1997: (v3.0b,c) - 1) Merging of the driver-developments of Klaus Kudielka and Michael Lang - in order to get a optimum and unified driver-release for the - IBM-SCSI-Subsystem-Adapter(s). - For people, using the Kernel-release >=2.1.0, module-support should - be no problem. For users, running under <2.1.0, module-support may not - work, because the methods have changed between 2.0.x and 2.1.x. - 2) Added some more effective statistics for /proc-output. - 3) Change typecasting at necessary points from (unsigned long) to - virt_to_bus(). - 4) Included #if... at special points to have specific adaption of the - driver to kernel 2.0.x and 2.1.x. It should therefore also run with - later releases. - 5) Magneto-Optical drives and medium-changers are also recognized, now. - Therefore, we have a completely gapfree recognition of all SCSI- - device-types, that are known by Linux up to kernel 2.1.31. - 6) The flag SCSI_IBMMCA_DEV_RESET has been inserted. If it is set within - the configuration, each connected SCSI-device will get a reset command - during boottime. This can be necessary for some special SCSI-devices. - This flag should be included in Config.in. - (See also the new Config.in file.) - Probable next improvement: bad disk handler. - - Michael Lang - - Sept 14 1997: (v3.0c) - 1) Some debugging and speed optimization applied. - - Michael Lang - - Dec 15, 1997 - - chrisb@truespectra.com - - made the front panel display thingy optional, specified from the - command-line via ibmmcascsi=display. Along the lines of the /LED - option for the OS/2 driver. - - fixed small bug in the LED display that would hang some machines. - - reversed ordering of the drives (using the - IBMMCA_SCSI_ORDER_STANDARD define). This is necessary for two main - reasons: - - users who've already installed Linux won't be screwed. Keep - in mind that not everyone is a kernel hacker. - - be consistent with the BIOS ordering of the drives. In the - BIOS, id 6 is C:, id 0 might be D:. With this scheme, they'd be - backwards. This confuses the crap out of those heathens who've - got a impure Linux installation (which, <wince>, I'm one of). - This whole problem arises because IBM is actually non-standard with - the id to BIOS mappings. You'll find, in fdomain.c, a similar - comment about a few FD BIOS revisions. The Linux (and apparently - industry) standard is that C: maps to scsi id (0,0). Let's stick - with that standard. - - Since this is technically a branch of my own, I changed the - version number to 3.0e-cpb. - - Jan 17, 1998: (v3.0f) - 1) Addition of some statistical info for /proc in proc_info. - 2) Taking care of the SCSI-assignment problem, dealed by Chris at Dec 15 - 1997. In fact, IBM is right, concerning the assignment of SCSI-devices - to driveletters. It is conform to the ANSI-definition of the SCSI- - standard to assign drive C: to SCSI-id 6, because it is the highest - hardware priority after the hostadapter (that has still today by - default everywhere id 7). Also realtime-operating systems that I use, - like LynxOS and OS9, which are quite industrial systems use top-down - numbering of the harddisks, that is also starting at id 6. Now, one - sits a bit between two chairs. On one hand side, using the define - IBMMCA_SCSI_ORDER_STANDARD makes Linux assigning disks conform to - the IBM- and ANSI-SCSI-standard and keeps this driver downward - compatible to older releases, on the other hand side, people is quite - habituated in believing that C: is assigned to (0,0) and much other - SCSI-BIOS do so. Therefore, I moved the IBMMCA_SCSI_ORDER_STANDARD - define out of the driver and put it into Config.in as subitem of - 'IBM SCSI support'. A help, added to Documentation/Configure.help - explains the differences between saying 'y' or 'n' to the user, when - IBMMCA_SCSI_ORDER_STANDARD prompts, so the ordinary user is enabled to - choose the way of assignment, depending on his own situation and gusto. - 3) Adapted SCSI_IBMMCA_DEV_RESET to the local naming convention, so it is - now called IBMMCA_SCSI_DEV_RESET. - 4) Optimization of proc_info and its subroutines. - 5) Added more in-source-comments and extended the driver description by - some explanation about the SCSI-device-assignment problem. - - Michael Lang - - Jan 18, 1998: (v3.0g) - 1) Correcting names to be absolutely conform to the later 2.1.x releases. - This is necessary for - IBMMCA_SCSI_DEV_RESET -> CONFIG_IBMMCA_SCSI_DEV_RESET - IBMMCA_SCSI_ORDER_STANDARD -> CONFIG_IBMMCA_SCSI_ORDER_STANDARD - - Michael Lang - - Jan 18, 1999: (v3.1 MCA-team internal) - 1) The multiple hosts structure is accessed from every subroutine, so there - is no longer the address of the device structure passed from function - to function, but only the hostindex. A call by value, nothing more. This - should really be understood by the compiler and the subsystem should get - the right values and addresses. - 2) The SCSI-subsystem detection was not complete and quite hugely buggy up - to now, compared to the technical manual. The interpretation of the pos2 - register is not as assumed by people before, therefore, I dropped a note - in the ibmmca_detect function to show the registers' interpretation. - The pos-registers of integrated SCSI-subsystems do not contain any - information concerning the IO-port offset, really. Instead, they contain - some info about the adapter, the chip, the NVRAM .... The I/O-port is - fixed to 0x3540 - 0x3547. There can be more than one adapters in the - slots and they get an offset for the I/O area in order to get their own - I/O-address area. See chapter 2 for detailed description. At least, the - detection should now work right, even on models other than 95. The 95ers - came happily around the bug, as their pos2 register contains always 0 - in the critical area. Reserved bits are not allowed to be interpreted, - therefore, IBM is allowed to set those bits as they like and they may - really vary between different PS/2 models. So, now, no interpretation - of reserved bits - hopefully no trouble here anymore. - 3) The command error, which you may get on models 55, 56, 57, 70, 77 and - P70 may have been caused by the fact, that adapters of older design do - not like sending commands to non-existing SCSI-devices and will react - with a command error as a sign of protest. While this error is not - present on IBM SCSI Adapter w/cache, it appears on IBM Integrated SCSI - Adapters. Therefore, I implemented a workaround to forgive those - adapters their protests, but it is marked up in the statistics, so - after a successful boot, you can see in /proc/scsi/ibmmca/<host_number> - how often the command errors have been forgiven to the SCSI-subsystem. - If the number is bigger than 0, you have a SCSI subsystem of older - design, what should no longer matter. - 4) ibmmca_getinfo() has been adapted very carefully, so it shows in the - slotn file really, what is senseful to be presented. - 5) ibmmca_register() has been extended in its parameter list in order to - pass the right name of the SCSI-adapter to Linux. - - Michael Lang - - Feb 6, 1999: (v3.1) - 1) Finally, after some 3.1Beta-releases, the 3.1 release. Sorry, for - the delayed release, but it was not finished with the release of - Kernel 2.2.0. - - Michael Lang - - Feb 10, 1999 (v3.1) - 1) Added a new commandline parameter called 'bypass' in order to bypass - every integrated subsystem SCSI-command consequently in case of - troubles. - 2) Concatenated read_capacity requests to the harddisks. It gave a lot - of troubles with some controllers and after I wanted to apply some - extensions, it jumped out in the same situation, on my w/cache, as like - on D. Weinehalls' Model 56, having integrated SCSI. This gave me the - decisive hint to move the code-part out and declare it global. Now - it seems to work far better and more stable. Let us see what - the world thinks of it... - 3) By the way, only Sony DAT-drives seem to show density code 0x13. A - test with a HP drive gave right results, so the problem is vendor- - specific and not a problem of the OS or the driver. - - Michael Lang - - Feb 18, 1999 (v3.1d) - 1) The abort command and the reset function have been checked for - inconsistencies. From the logical point of thinking, they work - at their optimum, now, but as the subsystem does not answer with an - interrupt, abort never finishes, sigh... - 2) Everything, that is accessed by a busmaster request from the adapter - is now declared as global variable, even the return-buffer in the - local checking phase. This assures, that no accesses to undefined memory - areas are performed. - 3) In ibmmca.h, the line unchecked_isa_dma is added with 1 in order to - avoid memory-pointers for the areas higher than 16MByte in order to - be sure, it also works on 16-Bit Microchannel bus systems. - 4) A lot of small things have been found, but nothing that endangered the - driver operations. Just it should be more stable, now. - - Michael Lang - - Feb 20, 1999 (v3.1e) - 1) I took the warning from the Linux Kernel Hackers Guide serious and - checked the cmd->result return value to the done-function very carefully. - It is obvious, that the IBM SCSI only delivers the tsb.dev_status, if - some error appeared, else it is undefined. Now, this is fixed. Before - any SCB command gets queued, the tsb.dev_status is set to 0, so the - cmd->result won't screw up Linux higher level drivers. - 2) The reset-function has slightly improved. This is still planned for - abort. During the abort and the reset function, no interrupts are - allowed. This is however quite hard to cope with, so the INT-status - register is read. When the interrupt gets queued, one can find its - status immediately on that register and is enabled to continue in the - reset function. I had no chance to test this really, only in a bogus - situation, I got this function running, but the situation was too much - worse for Linux :-(, so tests will continue. - 3) Buffers got now consistent. No open address mapping, as before and - therefore no further troubles with the unassigned memory segmentation - faults that scrambled probes on 95XX series and even on 85XX series, - when the kernel is done in a not so perfectly fitting way. - 4) Spontaneous interrupts from the subsystem, appearing without any - command previously queued are answered with a DID_BAD_INTR result. - 5) Taken into account ZP Gus' proposals to reverse the SCSI-device - scan order. As it does not work on Kernel 2.1.x or 2.2.x, as proposed - by him, I implemented it in a slightly derived way, which offers in - addition more flexibility. - - Michael Lang - - Apr 23, 2000 (v3.2pre1) - 1) During a very long time, I collected a huge amount of bug reports from - various people, trying really quite different things on their SCSI- - PS/2s. Today, all these bug reports are taken into account and should be - mostly solved. The major topics were: - - Driver crashes during boottime by no obvious reason. - - Driver panics while the midlevel-SCSI-driver is trying to inquire - the SCSI-device properties, even though hardware is in perfect state. - - Displayed info for the various slot-cards is interpreted wrong. - The main reasons for the crashes were two: - 1) The commands to check for device information like INQUIRY, - TEST_UNIT_READY, REQUEST_SENSE and MODE_SENSE cause the devices - to deliver information of up to 255 bytes. Midlevel drivers offer - 1024 bytes of space for the answer, but the IBM-SCSI-adapters do - not accept this, as they stick quite near to ANSI-SCSI and report - a COMMAND_ERROR message which causes the driver to panic. The main - problem was located around the INQUIRY command. Now, for all the - mentioned commands, the buffersize sent to the adapter is at - maximum 255 which seems to be a quite reasonable solution. - TEST_UNIT_READY gets a buffersize of 0 to make sure that no - data is transferred in order to avoid any possible command failure. - 2) On unsuccessful TEST_UNIT_READY, the mid-level driver has to send - a REQUEST_SENSE in order to see where the problem is located. This - REQUEST_SENSE may have various length in its answer-buffer. IBM - SCSI-subsystems report a command failure if the returned buffersize - is different from the sent buffersize, but this can be suppressed by - a special bit, which is now done and problems seem to be solved. - 2) Code adaption to all kernel-releases. Now, the 3.2 code compiles on - 2.0.x, 2.1.x, 2.2.x and 2.3.x kernel releases without any code-changes. - 3) Commandline-parameters are recognized again, even under Kernel 2.3.x or - higher. - - Michael Lang - - April 27, 2000 (v3.2pre2) - 1) Bypassed commands get read by the adapter by one cycle instead of two. - This increases SCSI-performance. - 2) Synchronous datatransfer is provided for sure to be 5 MHz on older - SCSI and 10 MHz on internal F/W SCSI-adapter. - 3) New commandline parameters allow to force the adapter to slow down while - in synchronous transfer. Could be helpful for very old devices. - - Michael Lang - - June 2, 2000 (v3.2pre5) - 1) Added Jim Shorney's contribution to make the activity indicator - flashing in addition to the LED-alphanumeric display-panel on - models 95A. To be enabled to choose this feature freely, a new - commandline parameter is added, called 'activity'. - 2) Added the READ_CONTROL bit for test_unit_ready SCSI-command. - 3) Added some suppress_exception bits to read_device_capacity and - all device_inquiry occurrences in the driver code. - 4) Complaints about the various KERNEL_VERSION implementations are - taken into account. Every local_LinuxKernelVersion occurrence is - now replaced by KERNEL_VERSION, defined in linux/version.h. - Corresponding changes were applied to ibmmca.h, too. This was a - contribution to all kernel-parts by Philipp Hahn. - - Michael Lang - - July 17, 2000 (v3.2pre8) - A long period of collecting bug reports from all corners of the world - now lead to the following corrections to the code: - 1) SCSI-2 F/W support crashed with a COMMAND ERROR. The reason for this - was that it is possible to disable Fast-SCSI for the external bus. - The feature-control command, where this crash appeared regularly, tried - to set the maximum speed of 10MHz synchronous transfer speed and that - reports a COMMAND ERROR if external bus Fast-SCSI is disabled. Now, - the feature-command probes down from maximum speed until the adapter - stops to complain, which is at the same time the maximum possible - speed selected in the reference program. So, F/W external can run at - 5 MHz (slow-) or 10 MHz (fast-SCSI). During feature probing, the - COMMAND ERROR message is used to detect if the adapter does not complain. - 2) Up to now, only combined busmode is supported, if you use external - SCSI-devices, attached to the F/W-controller. If dual bus is selected, - only the internal SCSI-devices get accessed by Linux. For most - applications, this should do fine. - 3) Wide-SCSI-addressing (16-Bit) is now possible for the internal F/W - bus on the F/W adapter. If F/W adapter is detected, the driver - automatically uses the extended PUN/LUN <-> LDN mapping tables, which - are now new from 3.2pre8. This allows PUNs between 0 and 15 and should - provide more fun with the F/W adapter. - 4) Several machines use the SCSI: POS registers for internal/undocumented - storage of system relevant info. This confused the driver, mainly on - models 9595, as it expected no onboard SCSI only, if all POS in - the integrated SCSI-area are set to 0x00 or 0xff. Now, the mechanism - to check for integrated SCSI is much more restrictive and these problems - should be history. - - Michael Lang - - July 18, 2000 (v3.2pre9) - This develop rather quickly at the moment. Two major things were still - missing in 3.2pre8: - 1) The adapter PUN for F/W adapters has 4-bits, while all other adapters - have 3-bits. This is now taken into account for F/W. - 2) When you select CONFIG_IBMMCA_SCSI_ORDER_STANDARD, you should - normally get the inverse probing order of your devices on the SCSI-bus. - The ANSI device order gets scrambled in version 3.2pre8!! Now, a new - and tested algorithm inverts the device-order on the SCSI-bus and - automatically avoids accidental access to whatever SCSI PUN the adapter - is set and works with SCSI- and Wide-SCSI-addressing. - - Michael Lang - - July 23, 2000 (v3.2pre10 unpublished) - 1) LED panel display supports wide-addressing in ibmmca=display mode. - 2) Adapter-information and autoadaption to address-space is done. - 3) Auto-probing for maximum synchronous SCSI transfer rate is working. - 4) Optimization to some embedded function calls is applied. - 5) Added some comment for the user to wait for SCSI-devices being probed. - 6) Finished version 3.2 for Kernel 2.4.0. It least, I thought it is but... - - Michael Lang - - July 26, 2000 (v3.2pre11) - 1) I passed a horrible weekend getting mad with NMIs on kernel 2.2.14 and - a model 9595. Asking around in the community, nobody except of me has - seen such errors. Weird, but I am trying to recompile everything on - the model 9595. Maybe, as I use a specially modified gcc, that could - cause problems. But, it was not the reason. The true background was, - that the kernel was compiled for i386 and the 9595 has a 486DX-2. - Normally, no troubles should appear, but for this special machine, - only the right processor support is working fine! - 2) Previous problems with synchronous speed, slowing down from one adapter - to the next during probing are corrected. Now, local variables store - the synchronous bitmask for every single adapter found on the MCA bus. - 3) LED alphanumeric panel support for XX95 systems is now showing some - alive rotator during boottime. This makes sense, when no monitor is - connected to the system. You can get rid of all display activity, if - you do not use any parameter or just ibmmcascsi=activity, for the - harddrive activity LED, existent on all PS/2, except models 8595-XXX. - If no monitor is available, please use ibmmcascsi=display, which works - fine together with the linuxinfo utility for the LED-panel. - - Michael Lang - - July 29, 2000 (v3.2) - 1) Submission of this driver for kernel 2.4test-XX and 2.2.17. - - Michael Lang - - December 28, 2000 (v3.2d / v4.0) - 1) The interrupt handler had some wrong statement to wait for. This - was done due to experimental reasons during 3.2 development but it - has shown that this is not stable enough. Going back to wait for the - adapter to be not busy is best. - 2) Inquiry requests can be shorter than 255 bytes of return buffer. Due - to a bug in the ibmmca_queuecommand routine, this buffer was forced - to 255 at minimum. If the memory address, this return buffer is pointing - to does not offer more space, invalid memory accesses destabilized the - kernel. - 3) version 4.0 is only valid for kernel 2.4.0 or later. This is necessary - to remove old kernel version dependent waste from the driver. 3.2d is - only distributed with older kernels but keeps compatibility with older - kernel versions. 4.0 and higher versions cannot be used with older - kernels anymore!! You must have at least kernel 2.4.0!! - 4) The commandline argument 'bypass' and all its functionality got removed - in version 4.0. This was never really necessary, as all troubles were - based on non-command related reasons up to now, so bypassing commands - did not help to avoid any bugs. It is kept in 3.2X for debugging reasons. - 5) Dynamic reassignment of ldns was again verified and analyzed to be - completely inoperational. This is corrected and should work now. - 6) All commands that get sent to the SCSI adapter were verified and - completed in such a way, that they are now completely conform to the - demands in the technical description of IBM. Main candidates were the - DEVICE_INQUIRY, REQUEST_SENSE and DEVICE_CAPACITY commands. They must - be transferred by bypassing the internal command buffer of the adapter - or else the response can be a random result. GET_POS_INFO would be more - safe in usage, if one could use the SUPRESS_EXCEPTION_SHORT, but this - is not allowed by the technical references of IBM. (Sorry, folks, the - model 80 problem is still a task to be solved in a different way.) - 7) v3.2d is still hold back for some days for testing, while 4.0 is - released. - - Michael Lang - - January 3, 2001 (v4.0a) - 1) A lot of complains after the 2.4.0-prerelease kernel came in about - the impossibility to compile the driver as a module. This problem is - solved. In combination with that problem, some unprecise declaration - of the function option_setup() gave some warnings during compilation. - This is solved, too by a forward declaration in ibmmca.c. - 2) #ifdef argument concerning CONFIG_SCSI_IBMMCA is no longer needed and - was entirely removed. - 3) Some switch statements got optimized in code, as some minor variables - in internal SCSI-command handlers. - - Michael Lang - - 4 To do - ------- - - IBM SCSI-2 F/W external SCSI bus support in separate mode! - - It seems that the handling of bad disks is really bad - - non-existent, in fact. However, a low-level driver cannot help - much, if such things happen. - - 5 Users' Manual - --------------- - 5.1 Commandline Parameters - -------------------------- - There exist several features for the IBM SCSI-subsystem driver. - The commandline parameter format is: - - ibmmcascsi=<command1>,<command2>,<command3>,... - - where commandN can be one of the following: - - display Owners of a model 95 or other PS/2 systems with an - alphanumeric LED display may set this to have their - display showing the following output of the 8 digits: - - ------DA - - where '-' stays dark, 'D' shows the SCSI-device id - and 'A' shows the SCSI hostindex, being currently - accessed. During boottime, this will give the message - - SCSIini* - - on the LED-panel, where the * represents a rotator, - showing the activity during the probing phase of the - driver which can take up to two minutes per SCSI-adapter. - adisplay This works like display, but gives more optical overview - of the activities on the SCSI-bus. The display will have - the following output: - - 6543210A - - where the numbers 0 to 6 light up at the shown position, - when the SCSI-device is accessed. 'A' shows again the SCSI - hostindex. If display nor adisplay is set, the internal - PS/2 harddisk LED is used for media-activities. So, if - you really do not have a system with a LED-display, you - should not set display or adisplay. Keep in mind, that - display and adisplay can only be used alternatively. It - is not recommended to use this option, if you have some - wide-addressed devices e.g. at the SCSI-2 F/W adapter in - your system. In addition, the usage of the display for - other tasks in parallel, like the linuxinfo-utility makes - no sense with this option. - activity This enables the PS/2 harddisk LED activity indicator. - Most PS/2 have no alphanumeric LED display, but some - indicator. So you should use this parameter to activate it. - If you own model 9595 (Server95), you can have both, the - LED panel and the activity indicator in parallel. However, - some PS/2s, like the 8595 do not have any harddisk LED - activity indicator, which means, that you must use the - alphanumeric LED display if you want to monitor SCSI- - activity. - bypass This is obsolete from driver version 4.0, as the adapters - got that far understood, that the selection between - integrated and bypassed commands should now work completely - correct! For historical reasons, the old description is - kept here: - This commandline parameter forces the driver never to use - SCSI-subsystems' integrated SCSI-command set. Except of - the immediate assign, which is of vital importance for - every IBM SCSI-subsystem to set its ldns right. Instead, - the ordinary ANSI-SCSI-commands are used and passed by the - controller to the SCSI-devices, therefore 'bypass'. The - effort, done by the subsystem is quite bogus and at a - minimum and therefore it should work everywhere. This - could maybe solve troubles with old or integrated SCSI- - controllers and nasty harddisks. Keep in mind, that using - this flag will slow-down SCSI-accesses slightly, as the - software generated commands are always slower than the - hardware. Non-harddisk devices always get read/write- - commands in bypass mode. On the most recent releases of - the Linux IBM-SCSI-driver, the bypass command should be - no longer a necessary thing, if you are sure about your - SCSI-hardware! - normal This is the parameter, introduced on the 2.0.x development - rail by ZP Gu. This parameter defines the SCSI-device - scan order in the new industry standard. This means, that - the first SCSI-device is the one with the lowest pun. - E.g. harddisk at pun=0 is scanned before harddisk at - pun=6, which means, that harddisk at pun=0 gets sda - and the one at pun=6 gets sdb. - ansi The ANSI-standard for the right scan order, as done by - IBM, Microware and Microsoft, scans SCSI-devices starting - at the highest pun, which means, that e.g. harddisk at - pun=6 gets sda and a harddisk at pun=0 gets sdb. If you - like to have the same SCSI-device order, as in DOS, OS-9 - or OS/2, just use this parameter. - fast SCSI-I/O in synchronous mode is done at 5 MHz for IBM- - SCSI-devices. SCSI-2 Fast/Wide Adapter/A external bus - should then run at 10 MHz if Fast-SCSI is enabled, - and at 5 MHz if Fast-SCSI is disabled on the external - bus. This is the default setting when nothing is - specified here. - medium Synchronous rate is at 50% approximately, which means - 2.5 MHz for IBM SCSI-adapters and 5.0 MHz for F/W ext. - SCSI-bus (when Fast-SCSI speed enabled on external bus). - slow The slowest possible synchronous transfer rate is set. - This means 1.82 MHz for IBM SCSI-adapters and 2.0 MHz - for F/W external bus at Fast-SCSI speed on the external - bus. - - A further option is that you can force the SCSI-driver to accept a SCSI- - subsystem at a certain I/O-address with a predefined adapter PUN. This - is done by entering - - commandN = I/O-base - commandN+1 = adapter PUN - - e.g. ibmmcascsi=0x3540,7 will force the driver to detect a SCSI-subsystem - at I/O-address 0x3540 with adapter PUN 7. Please only use this method, if - the driver does really not recognize your SCSI-adapter! With driver version - 3.2, this recognition of various adapters was hugely improved and you - should try first to remove your commandline arguments of such type with a - newer driver. I bet, it will be recognized correctly. Even multiple and - different types of IBM SCSI-adapters should be recognized correctly, too. - Use the forced detection method only as last solution! - - Examples: - - ibmmcascsi=adisplay - - This will use the advanced display mode for the model 95 LED alphanumeric - display. - - ibmmcascsi=display,0x3558,7 - - This will activate the default display mode for the model 95 LED display - and will force the driver to accept a SCSI-subsystem at I/O-base 0x3558 - with adapter PUN 7. - - 5.2 Troubleshooting - ------------------- - The following FAQs should help you to solve some major problems with this - driver. - - Q: "Reset SCSI-devices at boottime" halts the system at boottime, why? - A: This is only tested with the IBM SCSI Adapter w/cache. It is not - yet proven to run on other adapters, however you may be lucky. - In version 3.1d this has been hugely improved and should work better, - now. Normally you really won't need to activate this flag in the - kernel configuration, as all post 1989 SCSI-devices should accept - the reset-signal, when the computer is switched on. The SCSI- - subsystem generates this reset while being initialized. This flag - is really reserved for users with very old, very strange or self-made - SCSI-devices. - Q: Why is the SCSI-order of my drives mirrored to the device-order - seen from OS/2 or DOS ? - A: It depends on the operating system, if it looks at the devices in - ANSI-SCSI-standard (starting from pun 6 and going down to pun 0) or - if it just starts at pun 0 and counts up. If you want to be conform - with OS/2 and DOS, you have to activate this flag in the kernel - configuration or you should set 'ansi' as parameter for the kernel. - The parameter 'normal' sets the new industry standard, starting - from pun 0, scanning up to pun 6. This allows you to change your - opinion still after having already compiled the kernel. - Q: Why can't I find IBM MCA SCSI support in the config menu? - A: You have to activate MCA bus support, first. - Q: Where can I find the latest info about this driver? - A: See the file MAINTAINERS for the current WWW-address, which offers - updates, info and Q/A lists. At this file's origin, the webaddress - was: http://www.staff.uni-mainz.de/mlang/linux.html - Q: My SCSI-adapter is not recognized by the driver, what can I do? - A: Just force it to be recognized by kernel parameters. See section 5.1. - If this really happens, do also send e-mail to the maintainer, as - forced detection should be never necessary. Forced detection is in - principal some flaw of the driver adapter detection and goes into - bug reports. - Q: The driver screws up, if it starts to probe SCSI-devices, is there - some way out of it? - A: Yes, that was some recognition problem of the correct SCSI-adapter - and its I/O base addresses. Upgrade your driver to the latest release - and it should be fine again. - Q: I get a message: panic IBM MCA SCSI: command error .... , what can - I do against this? - A: Previously, I followed the way by ignoring command errors by using - ibmmcascsi=forgiveall, but this command no longer exists and is - obsolete. If such a problem appears, it is caused by some segmentation - fault of the driver, which maps to some unallowed area. The latest - version of the driver should be ok, as most bugs have been solved. - Q: There are still kernel panics, even after having set - ibmmcascsi=forgiveall. Are there other possibilities to prevent - such panics? - A: No, get just the latest release of the driver and it should work - better and better with increasing version number. Forget about this - ibmmcascsi=forgiveall, as also ignorecmd are obsolete.! - Q: Linux panics or stops without any comment, but it is probable, that my - harddisk(s) have bad blocks. - A: Sorry, the bad-block handling is still a feeble point of this driver, - but is on the schedule for development in the near future. - Q: Linux panics while dynamically assigning SCSI-ids or ldns. - A: If you disconnect a SCSI-device from the machine, while Linux is up - and the driver uses dynamical reassignment of logical device numbers - (ldn), it really gets "angry" if it won't find devices, that were still - present at boottime and stops Linux. - Q: The system does not recover after an abort-command has been generated. - A: This is regrettably true, as it is not yet understood, why the - SCSI-adapter does really NOT generate any interrupt at the end of - the abort-command. As no interrupt is generated, the abort command - cannot get finished and the system hangs, sorry, but checks are - running to hunt down this problem. If there is a real pending command, - the interrupt MUST get generated after abort. In this case, it - should finish well. - Q: The system gets in bad shape after a SCSI-reset, is this known? - A: Yes, as there are a lot of prescriptions (see the Linux Hackers' - Guide) what has to be done for reset, we still share the bad shape of - the reset functions with all other low level SCSI-drivers. - Astonishingly, reset works in most cases quite ok, but the harddisks - won't run in synchronous mode anymore after a reset, until you reboot. - Q: Why does my XXX w/Cache adapter not use read-prefetch? - A: Ok, that is not completely possible. If a cache is present, the - adapter tries to use it internally. Explicitly, one can use the cache - with a read prefetch command, maybe in future, but this requires - some major overhead of SCSI-commands that risks the performance to - go down more than it gets improved. Tests with that are running. - Q: I have a IBM SCSI-2 Fast/Wide adapter, it boots in some way and hangs. - A: Yes, that is understood, as for sure, your SCSI-2 Fast/Wide adapter - was in such a case recognized as integrated SCSI-adapter or something - else, but not as the correct adapter. As the I/O-ports get assigned - wrongly by that reason, the system should crash in most cases. You - should upgrade to the latest release of the SCSI-driver. The - recommended version is 3.2 or later. Here, the F/W support is in - a stable and reliable condition. Wide-addressing is in addition - supported. - Q: I get an Oops message and something like "killing interrupt". - A: The reason for this is that the IBM SCSI-subsystem only sends a - termination status back, if some error appeared. In former releases - of the driver, it was not checked, if the termination status block - is NULL. From version 3.2, it is taken care of this. - Q: I have a F/W adapter and the driver sees my internal SCSI-devices, - but ignores the external ones. - A: Select combined busmode in the IBM config-program and check for that - no SCSI-id on the external devices appears on internal devices. - Reboot afterwards. Dual busmode is supported, but works only for the - internal bus, yet. External bus is still ignored. Take care for your - SCSI-ids. If combined bus-mode is activated, on some adapters, - the wide-addressing is not possible, so devices with ids between 8 - and 15 get ignored by the driver & adapter! - Q: I have a 9595 and I get a NMI during heavy SCSI I/O e.g. during fsck. - A COMMAND ERROR is reported and characters on the screen are missing. - Warm reboot is not possible. Things look like quite weird. - A: Check the processor type of your 9595. If you have an 80486 or 486DX-2 - processor complex on your mainboard and you compiled a kernel that - supports 80386 processors, it is possible, that the kernel cannot - keep track of the PS/2 interrupt handling and stops on an NMI. Just - compile a kernel for the correct processor type of your PS/2 and - everything should be fine. This is necessary even if one assumes, - that some 80486 system should be downward compatible to 80386 - software. - Q: Some commands hang and interrupts block the machine. After some - timeout, the syslog reports that it tries to call abort, but the - machine is frozen. - A: This can be a busy wait bug in the interrupt handler of driver - version 3.2. You should at least upgrade to 3.2c if you use - kernel < 2.4.0 and driver version 4.0 if you use kernel 2.4.0 or - later (including all test releases). - Q: I have a PS/2 model 80 and more than 16 MBytes of RAM. The driver - completely refuses to work, reports NMIs, COMMAND ERRORs or other - ambiguous stuff. When reducing the RAM size down below 16 MB, - everything is running smoothly. - A: No real answer, yet. In any case, one should force the kernel to - present SCBs only below the 16 MBytes barrier. Maybe this solves the - problem. Not yet tried, but guessing that it could work. To get this, - set unchecked_isa_dma argument of ibmmca.h from 0 to 1. - - 5.3 Bug reports - -------------- - If you really find bugs in the source code or the driver will successfully - refuse to work on your machine, you should send a bug report to me. The - best for this is to follow the instructions on the WWW-page for this - driver. Fill out the bug-report form, placed on the WWW-page and ship it, - so the bugs can be taken into account with maximum efforts. But, please - do not send bug reports about this driver to Linus Torvalds or Leonard - Zubkoff, as Linus is buried in E-Mail and Leonard is supervising all - SCSI-drivers and won't have the time left to look inside every single - driver to fix a bug and especially DO NOT send modified code to Linus - Torvalds or Alan J. Cox which has not been checked here!!! They are both - quite buried in E-mail (as me, sometimes, too) and one should first check - for problems on my local teststand. Recently, I got a lot of - bug reports for errors in the ibmmca.c code, which I could not imagine, but - a look inside some Linux-distribution showed me quite often some modified - code, which did no longer work on most other machines than the one of the - modifier. Ok, so now that there is maintenance service available for this - driver, please use this address first in order to keep the level of - confusion low. Thank you! - - When you get a SCSI-error message that panics your system, a list of - register-entries of the SCSI-subsystem is shown (from Version 3.1d). With - this list, it is very easy for the maintainer to localize the problem in - the driver or in the configuration of the user. Please write down all the - values from this report and send them to the maintainer. This would really - help a lot and makes life easier concerning misunderstandings. - - Use the bug-report form (see 5.4 for its address) to send all the bug- - stuff to the maintainer or write e-mail with the values from the table. - - 5.4 Support WWW-page - -------------------- - The address of the IBM SCSI-subsystem supporting WWW-page is: - - http://www.staff.uni-mainz.de/mlang/linux.html - - Here you can find info about the background of this driver, patches, - troubleshooting support, news and a bugreport form. Please check that - WWW-page regularly for latest hints. If ever this URL changes, please - refer to the MAINTAINERS file in order to get the latest address. - - For the bugreport, please fill out the formular on the corresponding - WWW-page. Read the dedicated instructions and write as much as you - know about your problem. If you do not like such formulars, please send - some e-mail directly, but at least with the same information as required by - the formular. - - If you have extensive bug reports, including Oops messages and - screen-shots, please feel free to send it directly to the address - of the maintainer, too. The current address of the maintainer is: - - Michael Lang <langa2@kph.uni-mainz.de> - - 6 References - ------------ - IBM Corp., "Update for the PS/2 Hardware Interface Technical Reference, - Common Interfaces", Armonk, September 1991, PN 04G3281, - (available in the U.S. for $21.75 at 1-800-IBM-PCTB or in Germany for - around 40,-DM at "Hallo IBM"). - - IBM Corp., "Personal System/2 Micro Channel SCSI - Adapter with Cache Technical Reference", Armonk, March 1990, PN 68X2365. - - IBM Corp., "Personal System/2 Micro Channel SCSI - Adapter Technical Reference", Armonk, March 1990, PN 68X2397. - - IBM Corp., "SCSI-2 Fast/Wide Adapter/A Technical Reference - Dual Bus", - Armonk, March 1994, PN 83G7545. - - Friedhelm Schmidt, "SCSI-Bus und IDE-Schnittstelle - Moderne Peripherie- - Schnittstellen: Hardware, Protokollbeschreibung und Anwendung", 2. Aufl. - Addison Wesley, 1996. - - Michael K. Johnson, "The Linux Kernel Hackers' Guide", Version 0.6, Chapel - Hill - North Carolina, 1995 - - Andreas Kaiser, "SCSI TAPE BACKUP for OS/2 2.0", Version 2.12, Stuttgart - 1993 - - Helmut Rompel, "IBM Computerwelt GUIDE", What is what bei IBM., Systeme * - Programme * Begriffe, IWT-Verlag GmbH - Muenchen, 1988 - - 7 Credits to - ------------ - 7.1 People - ---------- - Klaus Grimm - who already a long time ago gave me the old code from the - SCSI-driver in order to get it running for some old machine - in our institute. - Martin Kolinek - who wrote the first release of the IBM SCSI-subsystem driver. - Chris Beauregard - who for a long time maintained MCA-Linux and the SCSI-driver - in the beginning. Chris, wherever you are: Cheers to you! - Klaus Kudielka - with whom in the 2.1.x times, I had a quite fruitful - cooperation to get the driver running as a module and to get - it running with multiple SCSI-adapters. - David Weinehall - for his excellent maintenance of the MCA-stuff and the quite - detailed bug reports and ideas for this driver (and his - patience ;-)). - Alan J. Cox - for his bug reports and his bold activities in cross-checking - the driver-code with his teststand. - - 7.2 Sponsors & Supporters - ------------------------- - "Hallo IBM", - IBM-Deutschland GmbH - the service of IBM-Deutschland for customers. Their E-Mail - service is unbeatable. Whatever old stuff I asked for, I - always got some helpful answers. - Karl-Otto Reimers, - IBM Klub - Sparte IBM Geschichte, Sindelfingen - for sending me a copy of the w/Cache manual from the - IBM-Deutschland archives. - Harald Staiger - for his extensive hardware donations which allows me today - still to test the driver in various constellations. - Erich Fritscher - for his very kind sponsoring. - Louis Ohland, - Charles Lasitter - for support by shipping me an IBM SCSI-2 Fast/Wide manual. - In addition, the contribution of various hardware is quite - decessive and will make it possible to add FWSR (RAID) - adapter support to the driver in the near future! So, - complaints about no RAID support won't remain forever. - Yes, folks, that is no joke, RAID support is going to rise! - Erik Weber - for the great deal we made about a model 9595 and the nice - surrounding equipment and the cool trip to Mannheim - second-hand computer market. In addition, I would like - to thank him for his exhaustive SCSI-driver testing on his - 95er PS/2 park. - Anthony Hogbin - for his direct shipment of a SCSI F/W adapter, which allowed - me immediately on the first stage to try it on model 8557 - together with onboard SCSI adapter and some SCSI w/Cache. - Andreas Hotz - for his support by memory and an IBM SCSI-adapter. Collecting - all this together now allows me to try really things with - the driver at maximum load and variety on various models in - a very quick and efficient way. - Peter Jennewein - for his model 30, which serves me as part of my teststand - and his cool remark about how you make an ordinary diskette - drive working and how to connect it to an IBM-diskette port. - Johannes Gutenberg-Universitaet, Mainz & - Institut fuer Kernphysik, Mainz Microtron (MAMI) - for the offered space, the link, placed on the central - homepage and the space to store and offer the driver and - related material and the free working times, which allow - me to answer all your e-mail. - - 8 Trademarks - ------------ - IBM, PS/2, OS/2, Microchannel are registered trademarks of International - Business Machines Corporation - - MS-DOS is a registered trademark of Microsoft Corporation - - Microware, OS-9 are registered trademarks of Microware Systems - - 9 Disclaimer - ------------ - Beside the GNU General Public License and the dependent disclaimers and disclaimers - concerning the Linux-kernel in special, this SCSI-driver comes without any - warranty. Its functionality is tested as good as possible on certain - machines and combinations of computer hardware, which does not exclude, - that data loss or severe damage of hardware is possible while using this - part of software on some arbitrary computer hardware or in combination - with other software packages. It is highly recommended to make backup - copies of your data before using this software. Furthermore, personal - injuries by hardware defects, that could be caused by this SCSI-driver are - not excluded and it is highly recommended to handle this driver with a - maximum of carefulness. - - This driver supports hardware, produced by International Business Machines - Corporation (IBM). - ------- -Michael Lang -(langa2@kph.uni-mainz.de) |