drm/i915: Avoid stalling on pending flips for legacy cursor updates
authorChris Wilson <chris@chris-wilson.co.uk>
Sun, 17 Apr 2016 19:42:46 +0000 (20:42 +0100)
committerChris Wilson <chris@chris-wilson.co.uk>
Mon, 18 Apr 2016 10:25:26 +0000 (11:25 +0100)
commitacf4e84d6167317ff21be5c03e1ea76ea5783701
tree39afd3478c1a4158064803db9645cc28bb2ab46e
parente6f577893d0a4c1f62585bc426ab32d88593d7da
drm/i915: Avoid stalling on pending flips for legacy cursor updates

The legacy cursor ioctl expects to be asynchronous with respect to other
screen updates, in particular page flips. As X updates the cursor from a
signal context, if the cursor blocks then it will stall both the input
and output chains causing bad stuttering and horrible UX.

Reported-and-tested-by: Rafael Ristovski <rafael.ristovski@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94980
Fixes: 5008e874edd34 ("drm/i915: Make wait_for_flips interruptible.")
Suggested-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: stable@vger.kernel.org
Link: http://patchwork.freedesktop.org/patch/msgid/1460922166-20292-1-git-send-email-chris@chris-wilson.co.uk
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
drivers/gpu/drm/i915/intel_display.c