On Fri, Apr 12, 2013 at 4:58 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> 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;
>
Acked-by: Yinghai Lu <yinghai@xxxxxxxxxx>
also could simplify it further.
---
drivers/pci/pci.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
Index: linux-2.6/drivers/pci/pci.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci.c
+++ linux-2.6/drivers/pci/pci.c
@@ -646,15 +646,11 @@ 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;
}
--
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