[Intel-gfx] slow graphics after Suspend to RAM

[John Harrigan]

* chris at chris-wilson.co.uk (Mar 17, 2011 @ 07:51+0000):
> On Wed, 16 Mar 2011 17:59:20 -0600, John Harrigan <jfharrigan at fedex.com> wrote:
> > I have a Lenovo X201 laptop with an i7-620M processor.  After I resume
> > from a Suspend to RAM the graphics are very slow.  Suspend to Disk does
> > not cause the same problem and doing a Suspend to Disk after a Suspend
> > to RAM fixes the problem.
> 
> Known problem. The PAT lose the WC bits for the GTT aperture on resume.
> There is a workaround that we can do: recreate the ioremapping upon
> resume. (But the root cause is not a gfx driver bug.)

I've opened a bug against memory management for this.

https://bugzilla.kernel.org/show_bug.cgi?id=31372

Chris, I tried to add you as a copy but I may not have done it
correctly.  Could you take a look to see if there's anything
else that could be added?  Thanks.