| From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> |
| Date: Fri, 12 Apr 2013 13:58:17 +0000 |
| Subject: PCI/PM: Fix fallback to PCI_D0 in pci_platform_power_transition() |
| |
| commit 769ba7212f2059ca9fe0c73371e3d415c8c1c529 upstream. |
| |
| 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. |
| |
| [bhelgaas: folded in Yinghai's simplification, added URL & stable info] |
| Reference: http://lkml.kernel.org/r/27806FC4E5928A408B78E88BBC67A2306F466BBA@ORSMSX101.amr.corp.intel.com |
| Reported-by: Chris J. Benenati <chris.j.benenati@intel.com> |
| Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> |
| Acked-by: Yinghai Lu <yinghai@kernel.org> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| drivers/pci/pci.c | 12 ++++-------- |
| 1 file changed, 4 insertions(+), 8 deletions(-) |
| |
| --- a/drivers/pci/pci.c |
| +++ b/drivers/pci/pci.c |
| @@ -664,15 +664,11 @@ 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) |
| - dev->current_state = PCI_D0; |
| - } else { |
| + } else |
| error = -ENODEV; |
| - /* Fall back to PCI_D0 if native PM is not supported */ |
| - if (!dev->pm_cap) |
| - dev->current_state = PCI_D0; |
| - } |
| + |
| + if (error && !dev->pm_cap) /* Fall back to PCI_D0 */ |
| + dev->current_state = PCI_D0; |
| |
| return error; |
| } |
