[Intel-gfx] [PATCH 3/3] drm/i915: don't rewrite the GTT on resume v2

[Daniel Vetter]

On Tue, Oct 30, 2012 at 10:32 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Tue, 30 Oct 2012 18:59:31 +0100, Daniel Vetter <daniel at ffwll.ch> wrote:
>> On Fri, Oct 26, 2012 at 10:08:38AM -0700, Jesse Barnes wrote:
>> > The BIOS shouldn't be touching this memory across suspend/resume, so
>> > just leave it alone.  This saves us ~50ms on resume on my T420.
>> >
>> > v2: change gtt restore default on pre-gen4 (Chris)
>> >     move needs_gtt_restore flag into dev_priv
>> >
>> > Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
>>
>> I've just realized: GGTT PTEs are stored in stolen mem, and hence not
>> restored accross S4.
>
> How to ruin the day. So we may as just evict everything upon suspend and
> rebuild as needed?

I think we already do that for pretty much all objects (I might have
been confused a bit). The problem is to correctly sprinkle the entire
gtt with scratch page entries ... I don't see an easy way to avoid
that.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch