drm/i915/gt: Ensure memory quiesced before invalidation

All memory traffic must be quiesced before requesting
an aux invalidation on platforms that use Aux CCS.

Fixes: 972282c4 ("drm/i915/gen12: Add aux table invalidate for all engines")
Requires: a2a4aa0eef3b ("drm/i915: Add the gen12_needs_ccs_aux_inv helper")
Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.8+
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230725001950.1014671-4-andi.shyti@linux.intel.com

drivers/gpu/drm/i915/gt/gen8_engine_cs.c

@@ -214,7 +214,11 @@ int gen12_emit_flush_rcs(struct i915_request *rq, u32 mode)
 {
 	struct intel_engine_cs *engine = rq->engine;
 
-	if (mode & EMIT_FLUSH) {
+	/*
+	 * On Aux CCS platforms the invalidation of the Aux
+	 * table requires quiescing memory traffic beforehand
+	 */
+	if (mode & EMIT_FLUSH || gen12_needs_ccs_aux_inv(engine)) {
 		u32 flags = 0;
 		int err;
 		u32 *cs;