[Intel-gfx] [RFC 10/11] drm/i915/preempt: Emit MI_ARB_CHECK before the start of user batch

[Michał Winiarski]

We should probably do this conditionally, based on whether preemption is
actually enabled.

Signed-off-by: Michał Winiarski <michal.winiarski at intel.com>
---
 drivers/gpu/drm/i915/intel_lrc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 869b96e..972f9bd 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1418,10 +1418,13 @@ static int gen8_emit_bb_start(struct drm_i915_gem_request *req,
 		req->ctx->ppgtt->pd_dirty_rings &= ~intel_engine_flag(req->engine);
 	}
 
-	cs = intel_ring_begin(req, 4);
+	cs = intel_ring_begin(req, 6);
 	if (IS_ERR(cs))
 		return PTR_ERR(cs);
 
+	*cs++ = MI_ARB_CHECK;
+	*cs++ = MI_NOOP;
+
 	/* FIXME(BDW): Address space and security selectors. */
 	*cs++ = MI_BATCH_BUFFER_START_GEN8 | (ppgtt << 8) | (dispatch_flags &
 		I915_DISPATCH_RS ? MI_BATCH_RESOURCE_STREAMER : 0);
-- 
2.9.3