Re: [PATCH] PCI: Set device power state to PCI_D0 for device without native PM support

From: Rafael J. Wysocki
Date: Thu Oct 06 2011 - 13:18:29 EST


On Thursday, October 06, 2011, Yinghai Lu wrote:
> On Wed, Oct 5, 2011 at 12:41 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> > Hi,
> >> drivers/pci/pci.c | 3 +++
> >> 1 files changed, 3 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> >> index e9651f0..ca8c82d 100644
> >> --- a/drivers/pci/pci.c
> >> +++ b/drivers/pci/pci.c
> >> @@ -664,6 +664,9 @@ static int pci_platform_power_transition(struct pci_dev *dev, pci_power_t state)
> >> 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 */
> >> + else if (!dev->pm_cap)
> >> + dev->current_state = PCI_D0;
> >> } else {
> >> error = -ENODEV;
> >> /* Fall back to PCI_D0 if native PM is not supported */
> >>
> >
> > I have some vague memories that we tried that and it broke something.
>
> Do have any hint for us to dig out the configuration for failing?
>
> >
> > How thoroughly has it been tested?
>
> tested in setups with intel cpus from Nehalem.

Can you test it on older hardware too, please?

Rafael
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