[Intel-gfx] [PATCH 39/71] drm/i915/chv: Implement WaDisableCSUnitClockGating:chv

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

This workaround is listed for CHV, but not for BDW. However BSpec notes
that on BDW CSunit clock gating is always disabled irrespective of the
relevant bit in the GEN6_UGCTL1 registers. For CHV however, such text
is not present in BSpec, so it seems safer to just set the bit.

Reviewed-by: Mika Kuoppala <mika.kuoppala at intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 53db89b..de9510e 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5397,6 +5397,10 @@ static void cherryview_init_clock_gating(struct drm_device *dev)
 	/* WaDisableSemaphoreAndSyncFlipWait:chv */
 	I915_WRITE(GEN6_RC_SLEEP_PSMI_CONTROL,
 		   _MASKED_BIT_ENABLE(GEN8_RC_SEMA_IDLE_MSG_DISABLE));
+
+	/* WaDisableCSUnitClockGating:chv */
+	I915_WRITE(GEN6_UCGCTL1, I915_READ(GEN6_UCGCTL1) |
+		   GEN6_CSUNIT_CLOCK_GATE_DISABLE);
 }
 
 static void g4x_init_clock_gating(struct drm_device *dev)
-- 
1.8.3.2