[Intel-gfx] [PATCH] drm/i915/bdw: Implement Wa4x4STCOptimizationDisable:bdw

[Damien Lespiau]

Not implementing this W/A can lead to hangs.

Cc: Ben Widawsky <benjamin.widawsky at intel.com>
Cc: Rafael Barbalho <rafael.barbalho at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h | 3 ++-
 drivers/gpu/drm/i915/intel_pm.c | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 0ebc20d..927a7c1 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1060,7 +1060,8 @@ enum punit_power_well {
 #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)
+#define   PIXEL_SUBSPAN_COLLECT_OPT_DISABLE	(1<<6)
+#define   GEN8_4x4_STC_OPTIMIZATION_DISABLE	(1<<6)
 
 #define GEN6_BLITTER_ECOSKPD	0x221d0
 #define   GEN6_BLITTER_LOCK_SHIFT			16
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index c1e2d75..b66a43b 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4882,6 +4882,10 @@ static void gen8_init_clock_gating(struct drm_device *dev)
 	/* WaDisableSDEUnitClockGating:bdw */
 	I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) |
 		   GEN8_SDEUNIT_CLOCK_GATE_DISABLE);
+
+	/* Wa4x4STCOptimizationDisable:bdw */
+	I915_WRITE(CACHE_MODE_1,
+		   _MASKED_BIT_ENABLE(GEN8_4x4_STC_OPTIMIZATION_DISABLE));
 }
 
 static void haswell_init_clock_gating(struct drm_device *dev)
-- 
1.8.3.1