From bb71ad880204b79d60331d3384103976e086cb9f Mon Sep 17 00:00:00 2001 From: Gary Hade Date: Mon, 12 May 2008 13:57:46 -0700 Subject: PCI: boot parameter to avoid expansion ROM memory allocation Contention for scarce PCI memory resources has been growing due to an increasing number of PCI slots in large multi-node systems. The kernel currently attempts by default to allocate memory for all PCI expansion ROMs so there has also been an increasing number of PCI memory allocation failures seen on these systems. This occurs because the BIOS either (1) provides insufficient PCI memory resource for all the expansion ROMs or (2) provides adequate PCI memory resource for expansion ROMs but provides the space in kernel unexpected BIOS assigned P2P non-prefetch windows. The resulting PCI memory allocation failures may be benign when related to memory requests for expansion ROMs themselves but in some cases they can occur when attempting to allocate space for more critical BARs. This can happen when a successful expansion ROM allocation request consumes memory resource that was intended for a non-ROM BAR. We have seen this happen during PCI hotplug of an adapter that contains a P2P bridge where successful memory allocation for an expansion ROM BAR on device behind the bridge consumed memory that was intended for a non-ROM BAR on the P2P bridge. In all cases the allocation failure messages can be very confusing for users. This patch provides a new 'pci=norom' kernel boot parameter that can be used to disable the default PCI expansion ROM memory resource allocation. This provides a way to avoid the above described issues on systems that do not contain PCI devices for which drivers or user-level applications depend on the default PCI expansion ROM memory resource allocation behavior. Signed-off-by: Gary Hade Signed-off-by: Jesse Barnes --- Documentation/kernel-parameters.txt | 3 +++ 1 file changed, 3 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index e07c432c731f..9cf7b34f2db0 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1496,6 +1496,9 @@ and is between 256 and 4096 characters. It is defined in the file Use with caution as certain devices share address decoders between ROMs and other resources. + norom [X86-32,X86_64] Do not assign address space to + expansion ROMs that do not already have + BIOS assigned address ranges. irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be assigned automatically to PCI devices. You can make the kernel exclude IRQs of your ISA cards -- cgit v1.2.3 From d8f3de0d2412bb91639cfefc5b3c79dbf3812212 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 12 Jun 2008 23:24:06 +0200 Subject: Suspend-related patches for 2.6.27 ACPI PM: Add possibility to change suspend sequence There are some systems out there that don't work correctly with our current suspend/hibernation code ordering. Provide a workaround for these systems allowing them to pass 'acpi_sleep=old_ordering' in the kernel command line so that it will use the pre-ACPI 2.0 ("old") suspend code ordering. Unfortunately, this requires us to add a platform hook to the resuming of devices for recovering the platform in case one of the device drivers' .suspend() routines returns error code. Namely, ACPI 1.0 specifies that _PTS should be called before suspending devices, but _WAK still should be called before resuming them in order to undo the changes made by _PTS. However, if there is an error during suspending devices, they are automatically resumed without returning control to the PM core, so the _WAK has to be called from within device_resume() in that cases. The patch also reorders and refactors the ACPI suspend/hibernation code to avoid duplication as far as reasonably possible. Signed-off-by: Rafael J. Wysocki Acked-by: Pavel Machek Signed-off-by: Jesse Barnes --- Documentation/kernel-parameters.txt | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 9cf7b34f2db0..18d793ea0dd3 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -147,10 +147,14 @@ and is between 256 and 4096 characters. It is defined in the file default: 0 acpi_sleep= [HW,ACPI] Sleep options - Format: { s3_bios, s3_mode, s3_beep } + Format: { s3_bios, s3_mode, s3_beep, old_ordering } See Documentation/power/video.txt for s3_bios and s3_mode. s3_beep is for debugging; it makes the PC's speaker beep as soon as the kernel's real-mode entry point is called. + old_ordering causes the ACPI 1.0 ordering of the _PTS + control method, wrt putting devices into low power + states, to be enforced (the ACPI 2.0 ordering of _PTS is + used by default). acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode Format: { level | edge | high | low } -- cgit v1.2.3 From 11c3b79218390a139f2d474ee1e983a672d5839a Mon Sep 17 00:00:00 2001 From: Joel Becker Date: Thu, 12 Jun 2008 14:00:18 -0700 Subject: configfs: Allow ->make_item() and ->make_group() to return detailed errors. The configfs operations ->make_item() and ->make_group() currently return a new item/group. A return of NULL signifies an error. Because of this, -ENOMEM is the only return code bubbled up the stack. Multiple folks have requested the ability to return specific error codes when these operations fail. This patch adds that ability by changing the ->make_item/group() ops to return an int. Also updated are the in-kernel users of configfs. Signed-off-by: Joel Becker --- Documentation/filesystems/configfs/configfs.txt | 10 ++++++---- Documentation/filesystems/configfs/configfs_example.c | 14 ++++++++------ 2 files changed, 14 insertions(+), 10 deletions(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/configfs/configfs.txt b/Documentation/filesystems/configfs/configfs.txt index 44c97e6accb2..15838d706ea2 100644 --- a/Documentation/filesystems/configfs/configfs.txt +++ b/Documentation/filesystems/configfs/configfs.txt @@ -233,10 +233,12 @@ accomplished via the group operations specified on the group's config_item_type. struct configfs_group_operations { - struct config_item *(*make_item)(struct config_group *group, - const char *name); - struct config_group *(*make_group)(struct config_group *group, - const char *name); + int (*make_item)(struct config_group *group, + const char *name, + struct config_item **new_item); + int (*make_group)(struct config_group *group, + const char *name, + struct config_group **new_group); int (*commit_item)(struct config_item *item); void (*disconnect_notify)(struct config_group *group, struct config_item *item); diff --git a/Documentation/filesystems/configfs/configfs_example.c b/Documentation/filesystems/configfs/configfs_example.c index 25151fd5c2c6..0b422acd470c 100644 --- a/Documentation/filesystems/configfs/configfs_example.c +++ b/Documentation/filesystems/configfs/configfs_example.c @@ -273,13 +273,13 @@ static inline struct simple_children *to_simple_children(struct config_item *ite return item ? container_of(to_config_group(item), struct simple_children, group) : NULL; } -static struct config_item *simple_children_make_item(struct config_group *group, const char *name) +static int simple_children_make_item(struct config_group *group, const char *name, struct config_item **new_item) { struct simple_child *simple_child; simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL); if (!simple_child) - return NULL; + return -ENOMEM; config_item_init_type_name(&simple_child->item, name, @@ -287,7 +287,8 @@ static struct config_item *simple_children_make_item(struct config_group *group, simple_child->storeme = 0; - return &simple_child->item; + *new_item = &simple_child->item; + return 0; } static struct configfs_attribute simple_children_attr_description = { @@ -359,20 +360,21 @@ static struct configfs_subsystem simple_children_subsys = { * children of its own. */ -static struct config_group *group_children_make_group(struct config_group *group, const char *name) +static int group_children_make_group(struct config_group *group, const char *name, struct config_group **new_group) { struct simple_children *simple_children; simple_children = kzalloc(sizeof(struct simple_children), GFP_KERNEL); if (!simple_children) - return NULL; + return -ENOMEM; config_group_init_type_name(&simple_children->group, name, &simple_children_type); - return &simple_children->group; + *new_group = &simple_children->group; + return 0; } static struct configfs_attribute group_children_attr_description = { -- cgit v1.2.3 From e56a99d5a42dcb91e622ae7a0289d8fb2ddabffb Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Mon, 14 Jul 2008 19:08:34 +0300 Subject: UBIFS: add brief documentation Signed-off-by: Artem Bityutskiy Signed-off-by: Adrian Hunter --- Documentation/filesystems/ubifs.txt | 164 ++++++++++++++++++++++++++++++++++++ 1 file changed, 164 insertions(+) create mode 100644 Documentation/filesystems/ubifs.txt (limited to 'Documentation') diff --git a/Documentation/filesystems/ubifs.txt b/Documentation/filesystems/ubifs.txt new file mode 100644 index 000000000000..540e9e7f59c5 --- /dev/null +++ b/Documentation/filesystems/ubifs.txt @@ -0,0 +1,164 @@ +Introduction +============= + +UBIFS file-system stands for UBI File System. UBI stands for "Unsorted +Block Images". UBIFS is a flash file system, which means it is designed +to work with flash devices. It is important to understand, that UBIFS +is completely different to any traditional file-system in Linux, like +Ext2, XFS, JFS, etc. UBIFS represents a separate class of file-systems +which work with MTD devices, not block devices. The other Linux +file-system of this class is JFFS2. + +To make it more clear, here is a small comparison of MTD devices and +block devices. + +1 MTD devices represent flash devices and they consist of eraseblocks of + rather large size, typically about 128KiB. Block devices consist of + small blocks, typically 512 bytes. +2 MTD devices support 3 main operations - read from some offset within an + eraseblock, write to some offset within an eraseblock, and erase a whole + eraseblock. Block devices support 2 main operations - read a whole + block and write a whole block. +3 The whole eraseblock has to be erased before it becomes possible to + re-write its contents. Blocks may be just re-written. +4 Eraseblocks become worn out after some number of erase cycles - + typically 100K-1G for SLC NAND and NOR flashes, and 1K-10K for MLC + NAND flashes. Blocks do not have the wear-out property. +5 Eraseblocks may become bad (only on NAND flashes) and software should + deal with this. Blocks on hard drives typically do not become bad, + because hardware has mechanisms to substitute bad blocks, at least in + modern LBA disks. + +It should be quite obvious why UBIFS is very different to traditional +file-systems. + +UBIFS works on top of UBI. UBI is a separate software layer which may be +found in drivers/mtd/ubi. UBI is basically a volume management and +wear-leveling layer. It provides so called UBI volumes which is a higher +level abstraction than a MTD device. The programming model of UBI devices +is very similar to MTD devices - they still consist of large eraseblocks, +they have read/write/erase operations, but UBI devices are devoid of +limitations like wear and bad blocks (items 4 and 5 in the above list). + +In a sense, UBIFS is a next generation of JFFS2 file-system, but it is +very different and incompatible to JFFS2. The following are the main +differences. + +* JFFS2 works on top of MTD devices, UBIFS depends on UBI and works on + top of UBI volumes. +* JFFS2 does not have on-media index and has to build it while mounting, + which requires full media scan. UBIFS maintains the FS indexing + information on the flash media and does not require full media scan, + so it mounts many times faster than JFFS2. +* JFFS2 is a write-through file-system, while UBIFS supports write-back, + which makes UBIFS much faster on writes. + +Similarly to JFFS2, UBIFS supports on-the-flight compression which makes +it possible to fit quite a lot of data to the flash. + +Similarly to JFFS2, UBIFS is tolerant of unclean reboots and power-cuts. +It does not need stuff like ckfs.ext2. UBIFS automatically replays its +journal and recovers from crashes, ensuring that the on-flash data +structures are consistent. + +UBIFS scales logarithmically (most of the data structures it uses are +trees), so the mount time and memory consumption do not linearly depend +on the flash size, like in case of JFFS2. This is because UBIFS +maintains the FS index on the flash media. However, UBIFS depends on +UBI, which scales linearly. So overall UBI/UBIFS stack scales linearly. +Nevertheless, UBI/UBIFS scales considerably better than JFFS2. + +The authors of UBIFS believe, that it is possible to develop UBI2 which +would scale logarithmically as well. UBI2 would support the same API as UBI, +but it would be binary incompatible to UBI. So UBIFS would not need to be +changed to use UBI2 + + +Mount options +============= + +(*) == default. + +norm_unmount (*) commit on unmount; the journal is committed + when the file-system is unmounted so that the + next mount does not have to replay the journal + and it becomes very fast; +fast_unmount do not commit on unmount; this option makes + unmount faster, but the next mount slower + because of the need to replay the journal. + + +Quick usage instructions +======================== + +The UBI volume to mount is specified using "ubiX_Y" or "ubiX:NAME" syntax, +where "X" is UBI device number, "Y" is UBI volume number, and "NAME" is +UBI volume name. + +Mount volume 0 on UBI device 0 to /mnt/ubifs: +$ mount -t ubifs ubi0_0 /mnt/ubifs + +Mount "rootfs" volume of UBI device 0 to /mnt/ubifs ("rootfs" is volume +name): +$ mount -t ubifs ubi0:rootfs /mnt/ubifs + +The following is an example of the kernel boot arguments to attach mtd0 +to UBI and mount volume "rootfs": +ubi.mtd=0 root=ubi0:rootfs rootfstype=ubifs + + +Module Parameters for Debugging +=============================== + +When UBIFS has been compiled with debugging enabled, there are 3 module +parameters that are available to control aspects of testing and debugging. +The parameters are unsigned integers where each bit controls an option. +The parameters are: + +debug_msgs Selects which debug messages to display, as follows: + + Message Type Flag value + + General messages 1 + Journal messages 2 + Mount messages 4 + Commit messages 8 + LEB search messages 16 + Budgeting messages 32 + Garbage collection messages 64 + Tree Node Cache (TNC) messages 128 + LEB properties (lprops) messages 256 + Input/output messages 512 + Log messages 1024 + Scan messages 2048 + Recovery messages 4096 + +debug_chks Selects extra checks that UBIFS can do while running: + + Check Flag value + + General checks 1 + Check Tree Node Cache (TNC) 2 + Check indexing tree size 4 + Check orphan area 8 + Check old indexing tree 16 + Check LEB properties (lprops) 32 + Check leaf nodes and inodes 64 + +debug_tsts Selects a mode of testing, as follows: + + Test mode Flag value + + Force in-the-gaps method 2 + Failure mode for recovery testing 4 + +For example, set debug_msgs to 5 to display General messages and Mount +messages. + + +References +========== + +UBIFS documentation and FAQ/HOWTO at the MTD web site: +http://www.linux-mtd.infradead.org/doc/ubifs.html +http://www.linux-mtd.infradead.org/faq/ubifs.html -- cgit v1.2.3 From bb7ee9b1ec15358af870a81b0c6a03af29417f99 Mon Sep 17 00:00:00 2001 From: Elias Oltmanns Date: Wed, 16 Jul 2008 20:33:48 +0200 Subject: Update documentation of HDIO_DRIVE_RESET ioctl Alter the entry for HDIO_DRIVE_RESET in Documentation/ioctl/hdio.txt to reflect a functional change in the driver. Besides, the entry has been inaccurate before. Signed-off-by: Elias Oltmanns Cc: "Alan Cox" Cc: "Randy Dunlap" Signed-off-by: Bartlomiej Zolnierkiewicz --- Documentation/ioctl/hdio.txt | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/ioctl/hdio.txt b/Documentation/ioctl/hdio.txt index c19efdeace2c..44d283d6b136 100644 --- a/Documentation/ioctl/hdio.txt +++ b/Documentation/ioctl/hdio.txt @@ -511,9 +511,8 @@ HDIO_DRIVE_RESET execute a device reset notes: - Abort any current command, prevent anything else from being - queued, execute a reset on the device, and issue BLKRRPART - ioctl on the block device. + Execute a reset on the device as soon as the current IO + operation has completed. Executes an ATAPI soft reset if applicable, otherwise executes an ATA soft reset on the controller. -- cgit v1.2.3 From 64a8f00ff19508b3962c8a932375dbae88bee4d6 Mon Sep 17 00:00:00 2001 From: Elias Oltmanns Date: Wed, 16 Jul 2008 20:33:48 +0200 Subject: IDE: Report errors during drive reset back to user space Make sure that each error condition during the execution of an HDIO_DRIVE_RESET ioctl is actually reported to the calling process. Also, unify the exit path of reset_pollfunc() when returning ide_stopped since the need of ->port_ops->reset_poll() to be treated specially has vanished (way back, it seems). Signed-off-by: Elias Oltmanns Cc: "Alan Cox" Cc: "Randy Dunlap" Signed-off-by: Bartlomiej Zolnierkiewicz --- Documentation/ioctl/hdio.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation') diff --git a/Documentation/ioctl/hdio.txt b/Documentation/ioctl/hdio.txt index 44d283d6b136..91a6ecbae0bb 100644 --- a/Documentation/ioctl/hdio.txt +++ b/Documentation/ioctl/hdio.txt @@ -508,6 +508,8 @@ HDIO_DRIVE_RESET execute a device reset error returns: EACCES Access denied: requires CAP_SYS_ADMIN + ENXIO No such device: phy dead or ctl_addr == 0 + EIO I/O error: reset timed out or hardware error notes: -- cgit v1.2.3 From a0bbaf83311cd995136c9047f174d79c1075ee2d Mon Sep 17 00:00:00 2001 From: Carlos Corbacho Date: Sat, 21 Jun 2008 09:09:08 +0100 Subject: acer-wmi: Remove LED colour comment from documentation This should have been removed when the colour was removed from the LED device name. Signed-off-by: Carlos Corbacho Signed-off-by: Len Brown Signed-off-by: Andi Kleen --- Documentation/laptops/acer-wmi.txt | 2 -- 1 file changed, 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/laptops/acer-wmi.txt b/Documentation/laptops/acer-wmi.txt index 79b7dbd22141..69b5dd4e5a59 100644 --- a/Documentation/laptops/acer-wmi.txt +++ b/Documentation/laptops/acer-wmi.txt @@ -174,8 +174,6 @@ The LED is exposed through the LED subsystem, and can be found in: The mail LED is autodetected, so if you don't have one, the LED device won't be registered. -If you have a mail LED that is not green, please report this to me. - Backlight ********* -- cgit v1.2.3 From 71b58cbb0c30d1f78636a48c4721529449d6ea37 Mon Sep 17 00:00:00 2001 From: Zhang Rui Date: Fri, 20 Jun 2008 09:42:47 +0800 Subject: ACPI: Enhance /sys/firmware/interrupts to allow enable/disable/clear from user-space Allow users to enable/disable/clear a specific & valid GPE/Fixed Event in user space. This is useful for debugging, especially for some interrupt storm issues. All wakeup GPEs are disabled and they can not be enabled at runtime, and we mark them as invalid. All GPEs that don't have a _Lxx/_Exx method are marked as invalid. All Fixed Events that don't have an event handler are marked as invalid and they can't be enabled until an event handler is registered. Signed-off-by: Zhang Rui Signed-off-by: Ling Ming Signed-off-by: Len Brown Signed-off-by: Andi Kleen --- Documentation/ABI/testing/sysfs-firmware-acpi | 127 ++++++++++++++++++-------- 1 file changed, 87 insertions(+), 40 deletions(-) (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-firmware-acpi b/Documentation/ABI/testing/sysfs-firmware-acpi index 9470ed9afcc0..f27be7d1a49f 100644 --- a/Documentation/ABI/testing/sysfs-firmware-acpi +++ b/Documentation/ABI/testing/sysfs-firmware-acpi @@ -29,46 +29,46 @@ Description: $ cd /sys/firmware/acpi/interrupts $ grep . * - error:0 - ff_gbl_lock:0 - ff_pmtimer:0 - ff_pwr_btn:0 - ff_rt_clk:0 - ff_slp_btn:0 - gpe00:0 - gpe01:0 - gpe02:0 - gpe03:0 - gpe04:0 - gpe05:0 - gpe06:0 - gpe07:0 - gpe08:0 - gpe09:174 - gpe0A:0 - gpe0B:0 - gpe0C:0 - gpe0D:0 - gpe0E:0 - gpe0F:0 - gpe10:0 - gpe11:60 - gpe12:0 - gpe13:0 - gpe14:0 - gpe15:0 - gpe16:0 - gpe17:0 - gpe18:0 - gpe19:7 - gpe1A:0 - gpe1B:0 - gpe1C:0 - gpe1D:0 - gpe1E:0 - gpe1F:0 - gpe_all:241 - sci:241 + error: 0 + ff_gbl_lock: 0 enable + ff_pmtimer: 0 invalid + ff_pwr_btn: 0 enable + ff_rt_clk: 2 disable + ff_slp_btn: 0 invalid + gpe00: 0 invalid + gpe01: 0 enable + gpe02: 108 enable + gpe03: 0 invalid + gpe04: 0 invalid + gpe05: 0 invalid + gpe06: 0 enable + gpe07: 0 enable + gpe08: 0 invalid + gpe09: 0 invalid + gpe0A: 0 invalid + gpe0B: 0 invalid + gpe0C: 0 invalid + gpe0D: 0 invalid + gpe0E: 0 invalid + gpe0F: 0 invalid + gpe10: 0 invalid + gpe11: 0 invalid + gpe12: 0 invalid + gpe13: 0 invalid + gpe14: 0 invalid + gpe15: 0 invalid + gpe16: 0 invalid + gpe17: 1084 enable + gpe18: 0 enable + gpe19: 0 invalid + gpe1A: 0 invalid + gpe1B: 0 invalid + gpe1C: 0 invalid + gpe1D: 0 invalid + gpe1E: 0 invalid + gpe1F: 0 invalid + gpe_all: 1192 + sci: 1194 sci - The total number of times the ACPI SCI has claimed an interrupt. @@ -89,6 +89,13 @@ Description: error - an interrupt that can't be accounted for above. + invalid: it's either a wakeup GPE or a GPE/Fixed Event that + doesn't have an event handler. + + disable: the GPE/Fixed Event is valid but disabled. + + enable: the GPE/Fixed Event is valid and enabled. + Root has permission to clear any of these counters. Eg. # echo 0 > gpe11 @@ -97,3 +104,43 @@ Description: None of these counters has an effect on the function of the system, they are simply statistics. + + Besides this, user can also write specific strings to these files + to enable/disable/clear ACPI interrupts in user space, which can be + used to debug some ACPI interrupt storm issues. + + Note that only writting to VALID GPE/Fixed Event is allowed, + i.e. user can only change the status of runtime GPE and + Fixed Event with event handler installed. + + Let's take power button fixed event for example, please kill acpid + and other user space applications so that the machine won't shutdown + when pressing the power button. + # cat ff_pwr_btn + 0 + # press the power button for 3 times; + # cat ff_pwr_btn + 3 + # echo disable > ff_pwr_btn + # cat ff_pwr_btn + disable + # press the power button for 3 times; + # cat ff_pwr_btn + disable + # echo enable > ff_pwr_btn + # cat ff_pwr_btn + 4 + /* + * this is because the status bit is set even if the enable bit is cleared, + * and it triggers an ACPI fixed event when the enable bit is set again + */ + # press the power button for 3 times; + # cat ff_pwr_btn + 7 + # echo disable > ff_pwr_btn + # press the power button for 3 times; + # echo clear > ff_pwr_btn /* clear the status bit */ + # echo disable > ff_pwr_btn + # cat ff_pwr_btn + 7 + -- cgit v1.2.3 From c1e3b377ad48febba6f91b8ae42c44ee4d4ab45e Mon Sep 17 00:00:00 2001 From: Zhao Yakui Date: Tue, 24 Jun 2008 17:58:53 +0800 Subject: ACPI: Create "idle=halt" bootparam "idle=halt" limits the idle loop to using the halt instruction. No MWAIT, no IO accesses, no C-states deeper than C1. If something is broken in the idle code, "idle=halt" is a less severe workaround than "idle=poll" which disables all power savings. Signed-off-by: Zhao Yakui Signed-off-by: Len Brown Signed-off-by: Andi Kleen --- Documentation/kernel-parameters.txt | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 312fe77764a4..65db7f4711aa 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -818,7 +818,7 @@ and is between 256 and 4096 characters. It is defined in the file See Documentation/ide/ide.txt. idle= [X86] - Format: idle=poll or idle=mwait + Format: idle=poll or idle=mwait, idle=halt Poll forces a polling idle loop that can slightly improves the performance of waking up a idle CPU, but will use a lot of power and make the system run hot. Not recommended. @@ -826,6 +826,8 @@ and is between 256 and 4096 characters. It is defined in the file to not use it because it doesn't save as much power as a normal idle loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same as idle=poll. + idle=halt. Halt is forced to be used for CPU idle. + In such case C2/C3 won't be used again. ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem Claim all unknown PCI IDE storage controllers. -- cgit v1.2.3 From da5e09a1b3e5a9fc0b15a3feb64e921ccc55ba74 Mon Sep 17 00:00:00 2001 From: Zhao Yakui Date: Tue, 24 Jun 2008 18:01:09 +0800 Subject: ACPI : Create "idle=nomwait" bootparam "idle=nomwait" disables the use of the MWAIT instruction from both C1 (C1_FFH) and deeper (C2C3_FFH) C-states. When MWAIT is unavailable, the BIOS and OS generally negotiate to use the HALT instruction for C1, and use IO accesses for deeper C-states. This option is useful for power and performance comparisons, and also to work around BIOS bugs where broken MWAIT support is advertised. http://bugzilla.kernel.org/show_bug.cgi?id=10807 http://bugzilla.kernel.org/show_bug.cgi?id=10914 Signed-off-by: Zhao Yakui Signed-off-by: Li Shaohua Signed-off-by: Len Brown Signed-off-by: Andi Kleen --- Documentation/kernel-parameters.txt | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 65db7f4711aa..5e497d16fb51 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -818,7 +818,7 @@ and is between 256 and 4096 characters. It is defined in the file See Documentation/ide/ide.txt. idle= [X86] - Format: idle=poll or idle=mwait, idle=halt + Format: idle=poll or idle=mwait, idle=halt, idle=nomwait Poll forces a polling idle loop that can slightly improves the performance of waking up a idle CPU, but will use a lot of power and make the system run hot. Not recommended. @@ -828,6 +828,7 @@ and is between 256 and 4096 characters. It is defined in the file as idle=poll. idle=halt. Halt is forced to be used for CPU idle. In such case C2/C3 won't be used again. + idle=nomwait. Disable mwait for CPU C-states ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem Claim all unknown PCI IDE storage controllers. -- cgit v1.2.3