drm/i915/icl: Add Wa_1409178092

We were missing this workaround which can cause hangs if fine grained
coherency was used.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190717180624.20354-7-tvrtko.ursulin@linux.intel.com

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

@@ -1297,6 +1297,12 @@ rcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
 		wa_write_or(wal,
 			    GEN7_SARCHKMD,
 			    GEN7_DISABLE_SAMPLER_PREFETCH);
+
+		/* Wa_1409178092:icl */
+		wa_write_masked_or(wal,
+				   GEN11_SCRATCH2,
+				   GEN11_COHERENT_PARTIAL_WRITE_MERGE_ENABLE,
+				   0);
 	}
 
 	if (IS_GEN_RANGE(i915, 9, 11)) {

drivers/gpu/drm/i915/i915_reg.h

@@ -7721,6 +7721,9 @@ enum {
 #define GEN7_L3SQCREG4				_MMIO(0xb034)
 #define  L3SQ_URB_READ_CAM_MATCH_DISABLE	(1 << 27)
 
+#define GEN11_SCRATCH2					_MMIO(0xb140)
+#define  GEN11_COHERENT_PARTIAL_WRITE_MERGE_ENABLE	(1 << 19)
+
 #define GEN8_L3SQCREG4				_MMIO(0xb118)
 #define  GEN11_LQSC_CLEAN_EVICT_DISABLE		(1 << 6)
 #define  GEN8_LQSC_RO_PERF_DIS			(1 << 27)