drm/i915/tgl: Implement Wa_1406941453

Enable Small PL for power benefit.
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Stuart Summers <stuart.summers@intel.com>
Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190713010940.17711-18-lucas.demarchi@intel.com
Link: https://patchwork.freedesktop.org/patch/msgid/20190726000226.26914-4-lucas.demarchi@intel.com

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

@@ -1260,6 +1260,13 @@ rcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
 {
 	struct drm_i915_private *i915 = engine->i915;
 
+	if (IS_GEN(i915, 12)) {
+		/* Wa_1406941453:tgl */
+		wa_masked_en(wal,
+			     SAMPLER_MODE,
+			     SAMPLER_ENABLE_SMALL_PL);
+	}
+
 	if (IS_GEN(i915, 11)) {
 		/* This is not an Wa. Enable for better image quality */
 		wa_masked_en(wal,

drivers/gpu/drm/i915/i915_reg.h

@@ -8965,6 +8965,9 @@ enum {
 #define   GEN9_DG_MIRROR_FIX_ENABLE	(1 << 5)
 #define   GEN9_CCS_TLB_PREFETCH_ENABLE	(1 << 3)
 
+#define SAMPLER_MODE			_MMIO(0xe18c)
+#define   SAMPLER_ENABLE_SMALL_PL	(1 << 15)
+
 #define GEN8_ROW_CHICKEN		_MMIO(0xe4f0)
 #define   FLOW_CONTROL_ENABLE		(1 << 15)
 #define   PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE	(1 << 8)