drm/i915: Protect gen7 irq_seqno_barrier with uncore lock
authorChris Wilson <chris@chris-wilson.co.uk>
Wed, 27 Apr 2016 08:02:01 +0000 (09:02 +0100)
committerChris Wilson <chris@chris-wilson.co.uk>
Thu, 28 Apr 2016 08:11:44 +0000 (09:11 +0100)
commitbcbdb6d01150dcc1769ddc9baaaf7f102f27f919
treee0e93c16a85afe9369480626aa079e2a0c11c64f
parent19ab4ed329393c0674f2b78fb71365a9461ee79b
drm/i915: Protect gen7 irq_seqno_barrier with uncore lock

Faced with sporadic machine hangs on gen7, that mimic the issue of
concurrent writes to the same cacheline and seem to start with
commit 9b9ed3093613 (drm/i915: Remove forcewake dance from seqno/irq
barrier on legacy gen6+), let us restore the spinlock around the mmio
read.

Fixes: 9b9ed3093613 (drm/i915: Remove forcewake dance from seqno/irq...)
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1461744121-27051-1-git-send-email-chris@chris-wilson.co.uk
Tested-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
drivers/gpu/drm/i915/intel_ringbuffer.c