linux-toradex.git/drivers/pci/pci.c, branch v3.4.9

PCI: EHCI: fix crash during suspend on ASUS computers

2012-07-16T16:04:39+00:00

commit dbf0e4c7257f8d684ec1a3c919853464293de66e upstream.

Quite a few ASUS computers experience a nasty problem, related to the
EHCI controllers, when going into system suspend.  It was observed
that the problem didn't occur if the controllers were not put into the
D3 power state before starting the suspend, and commit
151b61284776be2d6f02d48c23c3625678960b97 (USB: EHCI: fix crash during
suspend on ASUS computers) was created to do this.

It turned out this approach messed up other computers that didn't have
the problem -- it prevented USB wakeup from working.  Consequently
commit c2fb8a3fa25513de8fedb38509b1f15a5bbee47b (USB: add
NO_D3_DURING_SLEEP flag and revert 151b61284776be2) was merged; it
reverted the earlier commit and added a whitelist of known good board
names.

Now we know the actual cause of the problem.  Thanks to AceLan Kao for
tracking it down.

According to him, an engineer at ASUS explained that some of their
BIOSes contain a bug that was added in an attempt to work around a
problem in early versions of Windows.  When the computer goes into S3
suspend, the BIOS tries to verify that the EHCI controllers were first
quiesced by the OS.  Nothing's wrong with this, but the BIOS does it
by checking that the PCI COMMAND registers contain 0 without checking
the controllers' power state.  If the register isn't 0, the BIOS
assumes the controller needs to be quiesced and tries to do so.  This
involves making various MMIO accesses to the controller, which don't
work very well if the controller is already in D3.  The end result is
a system hang or memory corruption.

Since the value in the PCI COMMAND register doesn't matter once the
controller has been suspended, and since the value will be restored
anyway when the controller is resumed, we can work around the BIOS bug
simply by setting the register to 0 during system suspend.  This patch
(as1590) does so and also reverts the second commit mentioned above,
which is now unnecessary.

In theory we could do this for every PCI device.  However to avoid
introducing new problems, the patch restricts itself to EHCI host
controllers.

Finally the affected systems can suspend with USB wakeup working
properly.

Reference: https://bugzilla.kernel.org/show_bug.cgi?id=37632
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=42728
Based-on-patch-by: AceLan Kao 
Signed-off-by: Alan Stern 
Tested-by: Dâniel Fraga 
Tested-by: Javier Marcet 
Tested-by: Andrey Rahmatullin 
Tested-by: Oleksij Rempel 
Tested-by: Pavel Pisa 
Acked-by: Bjorn Helgaas 
Acked-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

USB: add NO_D3_DURING_SLEEP flag and revert 151b61284776be2

2012-06-22T18:37:13+00:00

commit c2fb8a3fa25513de8fedb38509b1f15a5bbee47b upstream.

This patch (as1558) fixes a problem affecting several ASUS computers:
The machine crashes or corrupts memory when going into suspend if the
ehci-hcd driver is bound to any controllers.  Users have been forced
to unbind or unload ehci-hcd before putting their systems to sleep.

After extensive testing, it was determined that the machines don't
like going into suspend when any EHCI controllers are in the PCI D3
power state.  Presumably this is a firmware bug, but there's nothing
we can do about it except to avoid putting the controllers in D3
during system sleep.

The patch adds a new flag to indicate whether the problem is present,
and avoids changing the controller's power state if the flag is set.
Runtime suspend is unaffected; this matters only for system suspend.
However as a side effect, the controller will not respond to remote
wakeup requests while the system is asleep.  Hence USB wakeup is not
functional -- but of course, this is already true in the current state
of affairs.

A similar patch has already been applied as commit
151b61284776be2d6f02d48c23c3625678960b97 (USB: EHCI: fix crash during
suspend on ASUS computers).  The patch supersedes that one and reverts
it.  There are two differences:

	The old patch added the flag at the USB level; this patch
	adds it at the PCI level.

	The old patch applied to all chipsets with the same vendor,
	subsystem vendor, and product IDs; this patch makes an
	exception for a known-good system (based on DMI information).

Signed-off-by: Alan Stern 
Tested-by: Dâniel Fraga 
Tested-by: Andrey Rahmatullin 
Tested-by: Steven Rostedt 
Reviewed-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PCI: Retry BARs restoration for Type 0 headers only

2012-04-17T01:33:35+00:00

Some shortcomings introduced into pci_restore_state() by commit
26f41062f28d ("PCI: check for pci bar restore completion and retry")
have been fixed by recent commit ebfc5b802fa76 ("PCI: Fix regression in
pci_restore_state(), v3"), but that commit treats all PCI devices as
those with Type 0 configuration headers.

That is not entirely correct, because Type 1 and Type 2 headers have
different layouts.  In particular, the area occupied by BARs in Type 0
config headers contains the secondary status register in Type 1 ones and
it doesn't make sense to retry the restoration of that register even if
the value read back from it after a write is not the same as the written
one (it very well may be different).

For this reason, make pci_restore_state() only retry the restoration
of BARs for Type 0 config headers.  This effectively makes it behave
as before commit 26f41062f28d for all header types except for Type 0.

Tested-by: Mikko Vinni 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Linus Torvalds

PCI: Fix regression in pci_restore_state(), v3

2012-04-15T20:06:29+00:00

Commit 26f41062f28d ("PCI: check for pci bar restore completion and
retry") attempted to address problems with PCI BAR restoration on
systems where FLR had not been completed before pci_restore_state() was
called, but it did that in an utterly wrong way.

First off, instead of retrying the writes for the BAR registers only, it
did that for all of the PCI config space of the device, including the
status register (whose value after the write quite obviously need not be
the same as the written one).  Second, it added arbitrary delay to
pci_restore_state() even for systems where the PCI config space
restoration was successful at first attempt.  Finally, the mdelay(10) it
added to every iteration of the writing loop was way too much of a delay
for any reasonable device.

All of this actually caused resume failures for some devices on Mikko's
system.

To fix the regression, make pci_restore_state() only retry the writes
for BAR registers and only wait if the first read from the register
doesn't return the written value.  Additionaly, make it wait for 1 ms,
instead of 10 ms, after every failing attempt to write into config
space.

Reported-by: Mikko Vinni 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Linus Torvalds

PCI / PCIe: Introduce command line option to disable ARI

2012-03-01T21:36:04+00:00

There are PCIe devices on the market that report ARI support but
then fail to initialize correctly when ARI is actually used.  This
leads to situations in which kernels 2.6.34 and newer fail to handle
systems where the previous kernels worked without any apparent
problems.  Unfortunately, it is currently unknown how many such
devices are there.

For this reason, introduce a new kernel command line option,
pci=noari, allowing users to disable PCIe ARI altogether if they
see problems with PCIe device initialization.

Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Jesse Barnes

PCI: Move "pci reassigndev resource alignment" out of quirks.c

2012-02-24T22:37:26+00:00

This isn't really a quirk; calling it directly from pci_add_device makes
more sense.

Signed-off-by: Yinghai Lu 
Signed-off-by: Jesse Barnes

PCI: prepare pci=realloc for multiple options

2012-02-24T16:47:42+00:00

Let the user could enable and disable with pci=realloc=on or pci=realloc=off

Also
1. move variable and functions near the place they are used.
2. change macro to function
3. change related functions and variable to static and _init
4. update parameter description accordingly.

This will let us add a config option to control default behavior, and
still allow the user to turn off automatic reallocation if it fails on
their platform until a permanent solution is found.

-v2: still honor pci=realloc, and treat it as pci=realloc=on
     also use enum instead of ...
-v3: update kernel-paramenters.txt according to Jesse.

Signed-off-by: Yinghai Lu 
Acked-by: Jesse Barnes 
Signed-off-by: Jesse Barnes

PCI: move pci_find_saved_cap out of linux/pci.h

2012-02-23T20:27:11+00:00

Only one user in driver/pci/pci.c, so we don't need to put it in global
pci.h

Reviewed-by: Bjorn Helgaas 
Signed-off-by: Yinghai Lu 
Signed-off-by: Jesse Barnes

PCI: fix memleak for pci dev removing during hotplug

2012-02-23T20:08:53+00:00

unreferenced object 0xffff880276d17700 (size 64):
  comm "swapper/0", pid 1, jiffies 4294897182 (age 3976.028s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 18 f9 de 76 02 88 ff ff  ...........v....
    10 00 00 00 0e 00 00 00 0f 28 40 00 00 00 00 00  .........(@.....
  backtrace:
    [] kmemleak_alloc+0x26/0x43
    [] __kmalloc+0x121/0x183
    [] pci_add_cap_save_buffer+0x35/0x7c
    [] pci_allocate_cap_save_buffers+0x1d/0x65
    [] pci_device_add+0x92/0xf1
    [] pci_scan_single_device+0x9f/0xa1
    [] pci_scan_slot.part.20+0x21/0x106
    [] pci_scan_slot+0x2b/0x35
    [] __pci_scan_child_bus+0x51/0x107
    [] pci_scan_bridge+0x376/0x6ae
    [] __pci_scan_child_bus+0xcd/0x107
    [] pci_scan_child_bus+0x11/0x2a
    [] pci_acpi_scan_root+0x18b/0x21c
    [] acpi_pci_root_add+0x1e1/0x42a
    [] acpi_device_probe+0x50/0x190
    [] really_probe+0x99/0x126

Need to free saved_buffer for capabilities.

Signed-off-by: Yinghai Lu 
Signed-off-by: Jesse Barnes

PCI: check for pci bar restore completion and retry

2012-02-14T16:45:02+00:00

On some OEM systems, pci_restore_state() is called while FLR has not yet
completed.  As a result, PCI BAR register restore is not successful.  This fix
reads back the restored value and compares it with saved value and re-tries 10
times before giving up.

Signed-off-by: Jean Guyader 
Signed-off-by: Eric Chanudet 
Signed-off-by: Allen Kay 
Signed-off-by: Jesse Barnes