Re: 2.6.29-rc3: tg3 dead after resume

Linus Torvalds
2009-01-30T23:51:50Z

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?

Linus