[Intel-gfx] [PATCH 1/7] drm/i915: implement ColorBlt w/a

[Daniel Vetter]

According to an internal workaround master list, we need to set bit 5
of register 9400 to avoid issues with color blits.

Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_reg.h      |    3 +++
 drivers/gpu/drm/i915/intel_display.c |    4 ++++
 2 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 3886cf0..233dbd5 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3727,6 +3727,9 @@
 #define  GT_FIFO_FREE_ENTRIES			0x120008
 #define    GT_FIFO_NUM_RESERVED_ENTRIES		20
 
+#define GEN6_UCGCTL1				0x9400
+# define GEN6_BLBUNIT_CLOCK_GATE_DISABLE		(1 << 5)
+
 #define GEN6_UCGCTL2				0x9404
 # define GEN6_RCZUNIT_CLOCK_GATE_DISABLE		(1 << 13)
 # define GEN6_RCPBUNIT_CLOCK_GATE_DISABLE		(1 << 12)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index d514719..aa0c6df 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8510,6 +8510,10 @@ static void gen6_init_clock_gating(struct drm_device *dev)
 	I915_WRITE(WM2_LP_ILK, 0);
 	I915_WRITE(WM1_LP_ILK, 0);
 
+	I915_WRITE(GEN6_UCGCTL1,
+		   I915_READ(GEN6_UCGCTL1) |
+		   GEN6_BLBUNIT_CLOCK_GATE_DISABLE);
+
 	/* According to the BSpec vol1g, bit 12 (RCPBUNIT) clock
 	 * gating disable must be set.  Failure to set it results in
 	 * flickering pixels due to Z write ordering failures after
-- 
1.7.7.6