Re: 2.6.29-rc3: tg3 dead after resume

Rafael J. Wysocki
2009-01-31T00:35:32Z

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().

pci_disable_enabled_device() is not called for the PCIe port driver, because
it has the legacy PM support.

What happens is

pci_pm_suspend(port) ->
pci_legacy_suspend(port) ->
pcie_portdrv_suspend(port) [this doesn't save the state]
pci_save_state(port)

and then, with interrupts off

pci_pm_suspend_noirq(port) ->
pci_legacy_suspend_late(port) ->
pcie_portdrv_suspend_late(port) ->
pci_save_state(port)

and I suspect this last pci_save_state() breaks things. I'm not sure why,
though.

Thanks,
Rafael