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authorRafael J. Wysocki <rjw@sisk.pl>2012-05-17 22:39:35 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-17 23:16:16 (GMT)
commit5c7dd710f691d1b44c39e32d2f05b4286ff51f99 (patch)
tree7c319291d09980496d2b01dcbb6d9138db9477be /drivers/acpi/scan.c
parenteea036475df8995e5b87cd6b8c8e682e071159cd (diff)
downloadlinux-fsl-qoriq-5c7dd710f691d1b44c39e32d2f05b4286ff51f99.tar.xz
ACPI / PCI / PM: Fix device PM regression related to D3hot/D3cold
Commit 1cc0c998fdf2 ("ACPI: Fix D3hot v D3cold confusion") introduced a bug in __acpi_bus_set_power() and changed the behavior of acpi_pci_set_power_state() in such a way that it generally doesn't work as expected if PCI_D3hot is passed to it as the second argument. First off, if ACPI_STATE_D3 (equal to ACPI_STATE_D3_COLD) is passed to __acpi_bus_set_power() and the explicit_set flag is set for the D3cold state, the function will try to execute AML method called "_PS4", which doesn't exist. Fix this by adding a check to ensure that the name of the AML method to execute for transitions to ACPI_STATE_D3_COLD is correct in __acpi_bus_set_power(). Also make sure that the explicit_set flag for ACPI_STATE_D3_COLD will be set if _PS3 is present and modify acpi_power_transition() to avoid accessing power resources for ACPI_STATE_D3_COLD, because they don't exist. Second, if PCI_D3hot is passed to acpi_pci_set_power_state() as the target state, the function will request a transition to ACPI_STATE_D3_HOT instead of ACPI_STATE_D3. However, ACPI_STATE_D3_HOT is now only marked as supported if the _PR3 AML method is defined for the given device, which is rare. This causes problems to happen on systems where devices were successfully put into ACPI D3 by pci_set_power_state(PCI_D3hot) which doesn't work now. In particular, some unused graphics adapters are not turned off as a result. To fix this issue restore the old behavior of acpi_pci_set_power_state(), which is to request a transition to ACPI_STATE_D3 (equal to ACPI_STATE_D3_COLD) if either PCI_D3hot or PCI_D3cold is passed to it as the argument. This approach is not ideal, because generally power should not be removed from devices if PCI_D3hot is the target power state, but since this behavior is relied on, we have no choice but to restore it at the moment and spend more time on designing a better solution in the future. References: https://bugzilla.kernel.org/show_bug.cgi?id=43228 Reported-by: rocko <rockorequin@hotmail.com> Reported-by: Cristian Rodríguez <crrodriguez@opensuse.org> Reported-and-tested-by: Peter <lekensteyn@gmail.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/acpi/scan.c')
-rw-r--r--drivers/acpi/scan.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 7417267..85cbfdc 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -908,6 +908,10 @@ static int acpi_bus_get_power_flags(struct acpi_device *device)
device->power.states[ACPI_STATE_D3].flags.valid = 1;
device->power.states[ACPI_STATE_D3].power = 0;
+ /* Set D3cold's explicit_set flag if _PS3 exists. */
+ if (device->power.states[ACPI_STATE_D3_HOT].flags.explicit_set)
+ device->power.states[ACPI_STATE_D3_COLD].flags.explicit_set = 1;
+
acpi_bus_init_power(device);
return 0;