On Tue, Apr 16, 2013 at 12:01 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > On Monday, April 15, 2013 02:18:18 PM Bjorn Helgaas wrote: >> On Fri, Apr 12, 2013 at 11:50 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote: >> > 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> >> >> I folded in Yinghai's simplification and added a URL to Chris's report >> and applied to my pci/rafael-pm branch: >> http://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git/log/?h=pci/rafael-pm >> >> If it still looks good to you, Rafael, I'll merge it to next for v3.10. > > Well, the simplification adds an extra check for error into both code paths, > so I'm not sure if it's really worth it (that's why I didn't do it originally > in the first place), but I suppose that's not a big deal. It looks good as far > as the correctness is concerned anyway. > >> I don't know what the user-visible effect of this is, and it's been >> around for a long time, but if you think this should go in v3.9 >> instead, let me know. > > I think v3.9+stable should be sufficient. It sounds like you meant to say "v3.10+stable should be sufficient". Is that right, or do you want me to push this to Linus before v3.9 is released? >> >> --- >> >> 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; >> > } > -- > I speak only for myself. > Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
