drm/i915/dg2: Add Wa_14015227452

Note that the bspec doesn't list the bit we're programming here (bit 11)
as being present on DG2, but we've confirmed with the hardware team that
this is a documentation mistake and the bit does indeed exist on all
Xe_HP-based platforms.
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220127194855.3963296-1-matthew.d.roper@intel.comReviewed-by: Swathi Dhanavanthri <swathi.dhanavanthri@intel.com>

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

@@ -2044,6 +2044,11 @@ rcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
 {
 	struct drm_i915_private *i915 = engine->i915;
 
+	if (IS_DG2(engine->i915)) {
+		/* Wa_14015227452:dg2 */
+		wa_masked_en(wal, GEN9_ROW_CHICKEN4, XEHP_DIS_BBL_SYSPIPE);
+	}
+
 	if (IS_DG2_GRAPHICS_STEP(engine->i915, G11, STEP_A0, STEP_B0)) {
 		/* Wa_14013392000:dg2_g11 */
 		wa_masked_en(wal, GEN7_ROW_CHICKEN2, GEN12_ENABLE_LARGE_GRF_MODE);

drivers/gpu/drm/i915/i915_reg.h

@@ -9762,6 +9762,7 @@ enum {
 
 #define GEN9_ROW_CHICKEN4				_MMIO(0xe48c)
 #define   GEN12_DISABLE_GRF_CLEAR			REG_BIT(13)
+#define   XEHP_DIS_BBL_SYSPIPE				REG_BIT(11)
 #define   GEN12_DISABLE_TDL_PUSH			REG_BIT(9)
 #define   GEN11_DIS_PICK_2ND_EU				REG_BIT(7)
 #define   GEN12_DISABLE_HDR_PAST_PAYLOAD_HOLD_FIX	REG_BIT(4)