tree 25248c541d8cd069cab517ae67350ba4def7e377
parent 06e562e7f515292ea7721475950f23554214adde
author Chris Wilson <chris@chris-wilson.co.uk> 1541665058 +0000
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1542788534 +0100

drm/i915/execlists: Force write serialisation into context image vs execution

commit 0a823e8fd4fd67726697854578f3584ee3a49b1d upstream.

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
(cherry picked from commit 987abd5c62f92ee4970b45aa077f47949974e615)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>