drm/i915: i8xx also doesn't like multiple oustanding pageflips
authorDaniel Vetter <daniel.vetter@ffwll.ch>
Wed, 4 Aug 2010 19:22:10 +0000 (21:22 +0200)
committerEric Anholt <eric@anholt.net>
Mon, 9 Aug 2010 18:24:30 +0000 (11:24 -0700)
commit6146b3d61925116e3fecce36c2fd873665bd6614
treeab3993e2ce1503fdd0926e14e342ad5b09d37d58
parent69d0b96c095468526009cb3104eee561c9252a84
drm/i915: i8xx also doesn't like multiple oustanding pageflips

My i855GM suffers from a 80k/s interrupt storm without this.
So add 2nd gen to the list of things that don't like more than
one outstanding pageflip request.

Furthermore I've changed the busy loop into a ringbuffer wait.
Busy-loops that don't check whether the chip died are simply evil.
And performance should actually improve, because there's usually
a decent amount of rendering queued on the gpu, hopefully rendering
that MI_WAIT into a noop by the time it's executed.

The current code holds dev->struct_mutex while executing this loop,
hence stalling all other gem activity anyway.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@kernel.org
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
[anholt: resolved against conflict]
Signed-off-by: Eric Anholt <eric@anholt.net>
drivers/gpu/drm/i915/intel_display.c