Re: Suspend problems in 2.6.31-rc6

Zhenyu Wang
2009-08-20T01:05:28Z

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On 2009.08.19 10:42:07 -0400, Alan Stern wrote:
> On Wed, 19 Aug 2009, Zhenyu Wang wrote:
>
> > Rafael, as I added this restore long time ago, pci core has changed in some way?
> > We had problem when reconfigure agp GTT space in resume, as we must be sure
> > gfx device's config space has been restored properly, and as 02:00 gfx device
> > restored later than host bridge 00:00 device, that came to my origin patch to
> > restore it earlier.
>
> Why did you do it that way? I mean, why not restore the gfx device's
> config space in its own resume routine instead of in the host bridge's
> resume routine?
>

That's the order issue I have mentioned. intel_agp is the pci driver for
host bridge (dev 00:00), and drm/i915 is the pci driver for gfx device
(dev 00:02). Host bridge will always resume earlier than gfx device, but
for intel_agp we need to access gfx device when reconfigure GTT in resume,
we can't wait until restore happen in i915 driver.

So there might be a conflict here, as i915 driver also do pci_restore_state()
after we did reconfigure in intel_agp driver, some configs may be corrupted
then. Although I haven't seen it in real testing.

--
Open Source Technology Center, Intel ltd.

$gpg --keyserver wwwkeys.pgp.net --recv-keys 4D781827

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