[Intel-gfx] slow graphics after Suspend to RAM

[Chris Wilson]

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 see the same slow-down regardless of whether X11 is running or not.
> I'm not doing 3D, I notice the slow-down in regular 2D stuff like
> scrolling a lot of text through a terminal window.

That's not regular 2D stuff, that's CPU fallback! You will only see a
slight performance difference (an order of magnitude and more, with
comparable decrease in power consumption whilst drawing) by switching to
the XRender paths in your terminal.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre