linux/drivers/pci
Alan Stern dbf0e4c725 PCI: EHCI: fix crash during suspend on ASUS computers
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
151b612847 (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 c2fb8a3fa2 (USB: add
NO_D3_DURING_SLEEP flag and revert 151b612847) 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 <acelan.kao@canonical.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Dâniel Fraga <fragabr@gmail.com>
Tested-by: Javier Marcet <jmarcet@gmail.com>
Tested-by: Andrey Rahmatullin <wrar@wrar.name>
Tested-by: Oleksij Rempel <bug-track@fisher-privat.net>
Tested-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Cc: stable <stable@vger.kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-10 09:52:05 -07:00
..
hotplug PCI: make acpihp use __pci_remove_bus_device instead 2012-02-27 12:17:16 -08:00
pcie PCI: fix uninitialized variable 'cap_mask' 2012-05-07 09:27:26 -06:00
.gitignore
access.c PCI: Introduce INTx check & mask API 2012-01-06 12:10:34 -08:00
ats.c Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
bus.c PCI: add struct pci_host_bridge_window with CPU/bus address offset 2012-02-23 20:19:00 -07:00
host-bridge.c PCI: add host bridge release support 2012-04-30 14:52:43 -06:00
hotplug-pci.c pci: Fix files needing export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:31:22 -04:00
hotplug.c
htirq.c pci: Fix files needing export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:31:22 -04:00
ioapic.c pci, x86/io-apic: Allow PCI_IOAPIC to be user configurable on x86 2011-12-06 09:21:05 +01:00
iov.c PCI: Rename pci_remove_bus_device to pci_stop_and_remove_bus_device 2012-02-27 12:12:18 -08:00
irq.c pci: Fix files needing export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:31:22 -04:00
Kconfig PCI: add a PCI resource reallocation config option 2012-02-24 09:38:59 -08:00
Makefile PCI changes for the 3.5 merge window: 2012-05-21 16:24:54 -07:00
msi.c x86/PCI: Expand the x86_msi_ops to have a restore MSIs. 2012-01-06 14:02:26 -08:00
msi.h PCI: MSI: Move MSI-X entry definition to pci_regs.h 2010-12-23 12:53:07 -08:00
of.c PCI: OF: Don't crash when bridge parent is NULL. 2011-08-19 08:51:37 -07:00
pci-acpi.c ACPI / PCI / PM: Fix device PM regression related to D3hot/D3cold 2012-05-17 16:16:16 -07:00
pci-driver.c PCI: EHCI: fix crash during suspend on ASUS computers 2012-07-10 09:52:05 -07:00
pci-label.c switch ->is_visible() to returning umode_t 2012-01-03 22:54:55 -05:00
pci-stub.c PCI: pci-stub: ignore zero-length id parameters 2010-12-23 12:53:52 -08:00
pci-sysfs.c vgaarb: Add support for setting the default video device (v2) 2012-04-24 09:50:15 +01:00
pci.c PCI: EHCI: fix crash during suspend on ASUS computers 2012-07-10 09:52:05 -07:00
pci.h PCI: add generic device into pci_host_bridge struct 2012-04-30 13:53:42 -06:00
probe.c Merge branch 'topic/stratus' into next 2012-05-07 09:23:27 -06:00
proc.c BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
quirks.c PCI: EHCI: fix crash during suspend on ASUS computers 2012-07-10 09:52:05 -07:00
remove.c PCI: export __pci_remove_bus_device 2012-02-27 12:16:55 -08:00
rom.c pci: Fix files needing export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:31:22 -04:00
search.c PCI: use for_each_pci_dev() 2010-07-30 09:47:22 -07:00
setup-bus.c Merge branch 'pci-next+probe_only+bus2res-fb127cb' of git://github.com/bjorn-helgaas/linux into linux-next 2012-02-24 14:25:33 -08:00
setup-irq.c PCI: Make the struct pci_dev * argument of pci_fixup_irqs const. 2011-07-22 08:26:06 -07:00
setup-res.c PCI: Move "pci reassigndev resource alignment" out of quirks.c 2012-02-24 14:37:26 -08:00
slot.c pci: add module.h to files implicitly relying on its presence. 2011-10-31 19:31:23 -04:00
syscall.c
vpd.c pci: Fix files needing export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:31:22 -04:00
xen-pcifront.c Two fixes for regressions: 2012-04-06 17:54:53 -07:00