[Intel-gfx] [PATCH] drm/i915/execlists: Flush the post-sync breadcrumb write harder

[Chris Wilson]

Quite rarely we see that the CS completion event fires before the
breadcrumb is coherent, which presumably is a result of the CS_STALL not
waiting for the post-sync operation. Try following in a DC_FLUSH into
the following pipecontrol to see if that makes any difference.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
---
 drivers/gpu/drm/i915/gt/intel_lrc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 80a3f1dbb456..48046d445733 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -2971,6 +2971,7 @@ static u32 *gen8_emit_fini_breadcrumb_rcs(struct i915_request *request, u32 *cs)
 	/* XXX flush+write+CS_STALL all in one upsets gem_concurrent_blt:kbl */
 	cs = gen8_emit_pipe_control(cs,
 				    PIPE_CONTROL_FLUSH_ENABLE |
+				    PIPE_CONTROL_DC_FLUSH_ENABLE |
 				    PIPE_CONTROL_CS_STALL,
 				    0);
 
-- 
2.23.0