intel driver suspend/resume failure

[James Bottomley]

On Sun, 2007-06-10 at 19:03 +0800, Wang Zhenyu wrote:
> On 2007.06.08 16:10:39 +0000, Jesse Barnes wrote:
> > On Friday, June 8, 2007 3:28:51 James Bottomley wrote:
> > > On Fri, 2007-06-08 at 15:17 -0700, Jesse Barnes wrote:
> > > > Can you send copies of video.state.0 prior to suspend and after?  That
> > > > way we'll know which registers are getting clobbered on resume...
> > >
> > > Sure; attached as video_state.0 and video_state.0.after (which is what I
> > > get on resume but before I overlay video_state.0).
> > >
> > > James
> > 
> > -0000e0 0020 0000 0000 0000 0000 0000 0000 0000
> > -0000f0 0000 3464 00ff 0000 0000 0005 0000 0000
> > +0000e0 0000 0000 0000 0000 0000 0000 0000 0000
> > +0000f0 0000 3464 0000 0000 0000 0005 0000 0000
> > 
> > I think the changes are just in the SWSMI scratch field and part of the legacy 
> > backlight register, so I'm not sure why this would make a difference for your 
> > machine, but I guess we should clear them...
> > 
> 
> Not sure if James has tried to clear this, and really fixed the resume?
> Or this field change was caused by something else?
> 
> Andreas Mohr has worked out i815 resume fix, which is on -mm tree now.
> see ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.22-rc4/2.6.22-rc4-mm2/broken-out/working-3d-dri-intel-agpko-resume-for-i815-chip.patch
> which also contains some facility code to debug this kind of resume problem,
> but it's a compile option, better to be a module param. This looks good to
> try and better to clean up the .suspend/.resume funcs.

Unfortunately not, since the suspend/resume plugs into the AGP
device ... these Fujitsu laptops seem to be directly coupled i915 chips,
so no AGP port.

I'm in two minds about this one ... as Greg says, the DRM driver could
do it ... on the other hand, a userspace restore of the PCI state does
work ... that seems a reasonable argument for simply doing the latter.

James