2 files changed, 9 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 75227009d0bb..ecc14f558744 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -5236,6 +5236,9 @@ enum skl_disp_power_wells {
 #define HSW_NDE_RSTWRN_OPT      0x46408
 #define  RESET_PCH_HANDSHAKE_ENABLE     (1<<4)
 
+#define FF_SLICE_CS_CHICKEN2                    0x02e4
+#define  GEN9_TSG_BARRIER_ACK_DISABLE           (1<<8)
+
 /* GEN7 chicken */
 #define GEN7_COMMON_SLICE_CHICKEN1              0x7010
 # define GEN7_CSC1_RHWO_OPT_DISABLE_IN_RCC      ((1<<10) | (1<<26))
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index a2b9c3e213f9..325f640c16c4 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -66,11 +66,16 @@ static void skl_init_clock_gating(struct drm_device *dev)
                            GEN8_SDEUNIT_CLOCK_GATE_DISABLE);
         }
 
-        if (INTEL_REVID(dev) <= SKL_REVID_D0)
+        if (INTEL_REVID(dev) <= SKL_REVID_D0) {
                 /* WaDisableHDCInvalidation:skl */
                 I915_WRITE(GAM_ECOCHK, I915_READ(GAM_ECOCHK) |
                            BDW_DISABLE_HDC_INVALIDATION);
 
+                /* WaDisableChickenBitTSGBarrierAckForFFSliceCS:skl */
+                I915_WRITE(FF_SLICE_CS_CHICKEN2,
+                           I915_READ(FF_SLICE_CS_CHICKEN2) |
+                           GEN9_TSG_BARRIER_ACK_DISABLE);
+        }
 
         if (INTEL_REVID(dev) <= SKL_REVID_E0)
                 /* WaDisableLSQCROPERFforOCL:skl */