drm/i915/execlists: Force write serialisation into context image vs execution
authorChris Wilson <chris@chris-wilson.co.uk>
Thu, 8 Nov 2018 08:17:38 +0000 (08:17 +0000)
committerChris Wilson <chris@chris-wilson.co.uk>
Thu, 8 Nov 2018 12:20:10 +0000 (12:20 +0000)
commit987abd5c62f92ee4970b45aa077f47949974e615
tree17c4ae1c651a1a64198fccdfb638813abbcd2592
parenta33e1ece777996ddddb1f23a30f8c66422ed0b68
drm/i915/execlists: Force write serialisation into context image vs execution

Ensure that the writes into the context image are completed prior to the
register mmio to trigger execution. Although previously we were assured
by the SDM that all writes are flushed before an uncached memory
transaction (our mmio write to submit the context to HW for execution),
we have empirical evidence to believe that this is not actually the
case.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108656
References: https://bugs.freedesktop.org/show_bug.cgi?id=108315
References: https://bugs.freedesktop.org/show_bug.cgi?id=106887
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181108081740.25615-1-chris@chris-wilson.co.uk
Cc: stable@vger.kernel.org
drivers/gpu/drm/i915/intel_lrc.c