drm/i915: fix for WaDisableDopClockGating:bdw

This workaround for BDW was incomplete as it also requires EUTC clock
gating to be disabled via UCGCTL1.

v2: read modify write UCGTL1 in broadwell_init_clock_gating (Ville)

Signed-off-by: Robert Bragg <robert@sixbynine.org>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170212133252.20990-1-robert@sixbynine.org
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index c0b0f5a..3c13be8 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -7229,6 +7229,14 @@ static void broadwell_init_clock_gating(struct drm_i915_private *dev_priv)
                   | KVM_CONFIG_CHANGE_NOTIFICATION_SELECT);
 
        lpt_init_clock_gating(dev_priv);
+
+       /* WaDisableDopClockGating:bdw
+        *
+        * Also see the CHICKEN2 write in bdw_init_workarounds() to disable DOP
+        * clock gating.
+        */
+       I915_WRITE(GEN6_UCGCTL1,
+                  I915_READ(GEN6_UCGCTL1) | GEN6_EU_TCUNIT_CLOCK_GATE_DISABLE);
 }
 
 static void haswell_init_clock_gating(struct drm_i915_private *dev_priv)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 0b9030c..95906c4 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -812,7 +812,11 @@ static int bdw_init_workarounds(struct intel_engine_cs *engine)
        /* WaDisableThreadStallDopClockGating:bdw (pre-production) */
        WA_SET_BIT_MASKED(GEN8_ROW_CHICKEN, STALL_DOP_GATING_DISABLE);
 
-       /* WaDisableDopClockGating:bdw */
+       /* WaDisableDopClockGating:bdw
+        *
+        * Also see the related UCGTCL1 write in broadwell_init_clock_gating()
+        * to disable EUTC clock gating.
+        */
        WA_SET_BIT_MASKED(GEN7_ROW_CHICKEN2,
                          DOP_CLOCK_GATING_DISABLE);