intel driver suspend/resume failure

James Bottomley James.Bottomley at SteelEye.com
Sat Jun 9 10:00:31 PDT 2007


On Sat, 2007-06-09 at 16:45 +0100, Matthew Garrett wrote:
> On Sat, Jun 09, 2007 at 12:21:03AM +0200, Lukas Hejtmanek wrote:
> 
> > this should be done by the kernel. what kernel version are you using?
> 
> Linux only saves the first 64 bytes of PCI config space, and even then 
> only if there's a PCI driver (so not drm) attached to the device.

For generic devices that's the best we can do ... a lot map registers
into configuration space above 64 (and registers can trigger actions as
well as just holding values).   It might be possible for the kernel to
identify the legacy PCI VGA device and save all 256 of its config space
values, but I think even that would be pretty dangerous.  As Jesse
showed, it seems to be the values at 0xe0-0xff that are needed to be
restored ... could the video driver not just save these on suspend and
restore them on resume.  Or would a script like I already have be
better?  I think debian already does something like this, so I could
probably persuade RH to do the same.

James





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