[Intel-gfx] [PATCH 1/8] drm/i915: Add WaDisableFenceDestinationToSLM:bdw

[Michel Thierry]

HDC_CHICKEN0 bit 14 (Fence Destination To SLM Disable) must be
programmed by software to 1h (Disable) to work around a LSLM unit issue.

WaDisableFenceDestinationToSLM is only needed for BDW E,F step.

Signed-off-by: Michel Thierry <michel.thierry at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h | 1 +
 drivers/gpu/drm/i915/intel_pm.c | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index ce70aa4..b8308cf 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -4701,6 +4701,7 @@ enum punit_power_well {
 
 /* GEN8 chicken */
 #define HDC_CHICKEN0				0x7300
+#define  HDC_FENCE_DESTINATION_TO_SLM_DISABLE	(1<<14)
 #define  HDC_FORCE_NON_COHERENT			(1<<4)
 
 /* WaCatErrorRejectionIssue */
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 6e03851..2c3087f 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5449,9 +5449,11 @@ static void gen8_init_clock_gating(struct drm_device *dev)
 	/* Use Force Non-Coherent whenever executing a 3D context. This is a
 	 * workaround for for a possible hang in the unlikely event a TLB
 	 * invalidation occurs during a PSD flush.
+	 * WaDisableFenceDestinationToSLM:bdw
 	 */
 	I915_WRITE(HDC_CHICKEN0,
 		   I915_READ(HDC_CHICKEN0) |
+		   _MASKED_BIT_ENABLE(HDC_FENCE_DESTINATION_TO_SLM_DISABLE) |
 		   _MASKED_BIT_ENABLE(HDC_FORCE_NON_COHERENT));
 
 	/* WaVSRefCountFullforceMissDisable:bdw */
-- 
1.9.0