[PATCH] drm/i915: enable HiZ Raw Stall Optimization

[Chia-I Wu <olvaffe@gmail.com>]

From: Chia-I Wu <olv@lunarg.com>

The optimization is available on Ivy Bridge and later, and is disabled by
default.  Enabling it helps certain workloads such as GLBenchmark TRex test.

Signed-off-by: Chia-I Wu <olv@lunarg.com>
Cc: Ian Romanick <ian.d.romanick@intel.com>
Cc: Chad Versace <chad.versace@linux.intel.com>

---
 drivers/gpu/drm/i915/i915_reg.h     | 2 ++
 drivers/gpu/drm/i915/i915_suspend.c | 9 +++++++--
 drivers/gpu/drm/i915/intel_pm.c     | 8 ++++++++
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index ee27421..bd90ef3 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -930,6 +930,8 @@
 #define   ECO_GATING_CX_ONLY	(1<<3)
 #define   ECO_FLIP_DONE		(1<<0)
 
+#define CACHE_MODE_0_GEN7	0x7000 /* IVB+ */
+#define   HIZ_RAW_STALL_OPT_DISABLE (1<<2)
 #define CACHE_MODE_1		0x7004 /* IVB+ */
 #define   PIXEL_SUBSPAN_COLLECT_OPT_DISABLE (1<<6)
 
diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
index 98790c7..13fefbd 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/drivers/gpu/drm/i915/i915_suspend.c
@@ -398,7 +398,9 @@ int i915_save_state(struct drm_device *dev)
 	intel_disable_gt_powersave(dev);
 
 	/* Cache mode state */
-	if (INTEL_INFO(dev)->gen < 7)
+	if (INTEL_INFO(dev)->gen >= 7)
+		dev_priv->regfile.saveCACHE_MODE_0 = I915_READ(CACHE_MODE_0_GEN7);
+	else
 		dev_priv->regfile.saveCACHE_MODE_0 = I915_READ(CACHE_MODE_0);
 
 	/* Memory Arbitration state */
@@ -448,7 +450,10 @@ int i915_restore_state(struct drm_device *dev)
 	}
 
 	/* Cache mode state */
-	if (INTEL_INFO(dev)->gen < 7)
+	if (INTEL_INFO(dev)->gen >= 7)
+		I915_WRITE(CACHE_MODE_0_GEN7, dev_priv->regfile.saveCACHE_MODE_0 |
+			   0xffff0000);
+	else
 		I915_WRITE(CACHE_MODE_0, dev_priv->regfile.saveCACHE_MODE_0 |
 			   0xffff0000);
 
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 26c29c1..d6ddc39 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5355,6 +5355,10 @@ static void haswell_init_clock_gating(struct drm_device *dev)
 	/* WaVSRefCountFullforceMissDisable:hsw */
 	gen7_setup_fixed_func_scheduler(dev_priv);
 
+	/* enable HiZ Raw Stall Optimization */
+	I915_WRITE(CACHE_MODE_0_GEN7,
+		   _MASKED_BIT_DISABLE(HIZ_RAW_STALL_OPT_DISABLE));
+
 	/* WaDisable4x2SubspanOptimization:hsw */
 	I915_WRITE(CACHE_MODE_1,
 		   _MASKED_BIT_ENABLE(PIXEL_SUBSPAN_COLLECT_OPT_DISABLE));
@@ -5445,6 +5449,10 @@ static void ivybridge_init_clock_gating(struct drm_device *dev)
 	/* WaVSRefCountFullforceMissDisable:ivb */
 	gen7_setup_fixed_func_scheduler(dev_priv);
 
+	/* enable HiZ Raw Stall Optimization */
+	I915_WRITE(CACHE_MODE_0_GEN7,
+		   _MASKED_BIT_DISABLE(HIZ_RAW_STALL_OPT_DISABLE));
+
 	/* WaDisable4x2SubspanOptimization:ivb */
 	I915_WRITE(CACHE_MODE_1,
 		   _MASKED_BIT_ENABLE(PIXEL_SUBSPAN_COLLECT_OPT_DISABLE));
-- 
1.8.5.3