[Intel-gfx] [PATCH 2/2] drm/i915: Repeat evictions whilst pageflip completions are outstanding

[Bloomfield, Jon]

> From: intel-gfx-bounces at lists.freedesktop.org [mailto:intel-gfx-
> bounces at lists.freedesktop.org] On Behalf Of Chris Wilson
> Sent: Monday, January 20, 2014 10:18 AM
> To: intel-gfx at lists.freedesktop.org
> Subject: [Intel-gfx] [PATCH 2/2] drm/i915: Repeat evictions whilst pageflip
> completions are outstanding
> 
> Since an old pageflip will keep its scanout buffer object pinned until it has
> executed its unpin task on the common workqueue, we can clog up our
> GGTT with stale pinned objects. As we cannot flush those workqueues
> without dropping our locks, we have to resort to falling back to userspace
> and telling them to repeat the operation in order to have a chance to run our
> workqueues and free up the required memory. If we fail, then we are forced
> to report ENOSPC back to userspace causing the operation to fail and best-
> case scenario is that it introduces temporary corruption.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Reviewed-by: Jon Bloomfield <jon.bloomfield at intel.com>