drm/i915: Reset last_retired_head when resetting ring
authorChris Wilson <chris@chris-wilson.co.uk>
Mon, 28 May 2012 21:33:02 +0000 (22:33 +0100)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Tue, 29 May 2012 18:06:58 +0000 (20:06 +0200)
commitc3b20037926e607b6cdaecbf9d3103e2ca63bc31
tree95b4dc9d2a57a17d5be75f03868496aa70b51508
parent1c780f2cfec8b533b9cfda77209b4e3e7adaddbf
drm/i915: Reset last_retired_head when resetting ring

When we reset the ring control registers, including the HEAD and TAIL of
the ring, we also need to reset associated state. In this instance, we
were failing to reset the cached value of ring->last_retired_head and so
upon the first request for more space following a resume would
potentially (depending on a narrow race window) believe that the HEAD had
advanced much further than reality.

This is a regression from:

commit a71d8d94525e8fd855c0466fb586ae1cb008f3a2
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Wed Feb 15 11:25:36 2012 +0000

    drm/i915: Record the tail at each request and use it to estimate the head

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org # 3.4
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drivers/gpu/drm/i915/intel_ringbuffer.c