[PATCH] PCI / PM: Fix fallback to PCI_D0 in pci_platform_power_transition()

From: Rafael J. Wysocki
Date: Fri Apr 12 2013 - 19:50:36 EST

From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Commit b51306c (PCI: Set device power state to PCI_D0 for device
without native PM support) modified pci_platform_power_transition()
by adding code causing dev->current_state for devices that don't
support native PCI PM but are power-manageable by the platform to be
changed to PCI_D0 regardless of the value returned by the preceding
platform_pci_set_power_state(). In particular, that also is done
if the platform_pci_set_power_state() has been successful, which
causes the correct power state of the device set by
pci_update_current_state() in that case to be overwritten by PCI_D0.

Fix that mistake by making the fallback to PCI_D0 only happen if
the platform_pci_set_power_state() has returned an error.

Reported-by: Chris J. Benenati <chris.j.benenati@xxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
drivers/pci/pci.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

Index: linux-pm/drivers/pci/pci.c
--- linux-pm.orig/drivers/pci/pci.c
+++ linux-pm/drivers/pci/pci.c
@@ -646,8 +646,7 @@ static int pci_platform_power_transition
error = platform_pci_set_power_state(dev, state);
if (!error)
pci_update_current_state(dev, state);
- /* Fall back to PCI_D0 if native PM is not supported */
- if (!dev->pm_cap)
+ else if (!dev->pm_cap) /* Fall back to PCI_D0 */
dev->current_state = PCI_D0;
} else {
error = -ENODEV;

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