Re: 2.6.29-rc3: tg3 dead after resume

Rafael J. Wysocki
2009-01-31T00:08:11Z

On Saturday 31 January 2009, Linus Torvalds wrote:
>
> On Sat, 31 Jan 2009, Rafael J. Wysocki wrote:
> >
> > I wonder if this change makes any difference:
> >
> > --- linux-2.6.orig/drivers/pci/pci-driver.c
> > +++ linux-2.6/drivers/pci/pci-driver.c
> > @@ -501,6 +501,9 @@ static int pci_pm_suspend(struct device
> > if (pci_has_legacy_pm_support(pci_dev))
> > return pci_legacy_suspend(dev, PMSG_SUSPEND);
> >
> > + if (!drv || !drv->pm)
> > + return 0;
> > +
> > if (drv && drv->pm && drv->pm->suspend) {
> > error = drv->pm->suspend(dev);
> > suspend_report_result(drv->pm->suspend, error);
>
> I don't think that's right. Now you don't end up calling
> pci_pm_default_suspend_generic() at all, and this no pci_save_state().
>
> But I think it could easily be the call to pci_disable_enabled_device().
> It does that
>
> if (atomic_read(&dev->enable_cnt))
> do_pci_disable_device(dev);
>
> and that ends up disabling PCI_COMMAND_MASTER and then calling
> pcibios_disable_device().
>
> Any device we have ever done pci_enable_device() on would trigger this,
> which includes PCIE bridges, for example. And while the pcie driver does
> that
>
> pcie_portdrv_restore_config ->
> pci_enable_device(dev);
>
> thing to re-enable it, that's a no-op since the enable_count is already
> non-zero.
>
> And we do try to restore it (pci_restore_standard_config() will call
> pci_restore_state()), but since we've done the
> pci_disable_enabled_device() _before_ we did the pci_save_state(), we now
> restore a non-working setup.
>
> I think. The rules are too damn subtle there. Rafael, can you look around
> a bit?

Sure, I'm looking at it right now.

Rafael