[PATCH] drm/i915: Display WA #1133 WaFbcSkipSegments:cnl, glk

[Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>]

Skip compressing 1 segment at the end of the frame,
avoid a pixel count mismatch nuke event when last active
pixel and dummy pixel has same color for Odd Plane
Width / Height.

For both platforms Gemini Lake and Cannon Lake.

v2: Use function-like macro and also use mask to clean
    to make sure bit 11 is 0. (Suggested by Paulo).
v3: Add Display WA notation and also apply for GLK.
    Both Forgotten on v2.
    Using "GLK_" prefix since GLK came before CNL.

Cc: Imre Deak <imre.deak@xxxxxxxxx>
Cc: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
---
 drivers/gpu/drm/i915/i915_reg.h |  3 +++
 drivers/gpu/drm/i915/intel_pm.c | 14 ++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index c718c2f2eaeb..fbf824b6e37a 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2940,6 +2940,9 @@ enum i915_power_well_id {
 #define ILK_DPFC_CHICKEN	_MMIO(0x43224)
 #define   ILK_DPFC_DISABLE_DUMMY0 (1<<8)
 #define   ILK_DPFC_NUKE_ON_ANY_MODIFICATION	(1<<23)
+#define   GLK_SKIP_SEG_EN		(1<<12)
+#define   GLK_SKIP_SEG_COUNT_MASK	(3<<10)
+#define   GLK_SKIP_SEG_COUNT(x)		((x)<<10)
 #define ILK_FBC_RT_BASE		_MMIO(0x2128)
 #define   ILK_FBC_RT_VALID	(1<<0)
 #define   SNB_FBC_FRONT_BUFFER	(1<<1)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index b0ba5a1018cd..324011f40373 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -125,6 +125,7 @@ static void bxt_init_clock_gating(struct drm_i915_private *dev_priv)
 
 static void glk_init_clock_gating(struct drm_i915_private *dev_priv)
 {
+	u32 val;
 	gen9_init_clock_gating(dev_priv);
 
 	/*
@@ -144,6 +145,11 @@ static void glk_init_clock_gating(struct drm_i915_private *dev_priv)
 		I915_WRITE(CHICKEN_MISC_2, val);
 	}
 
+	/* Display WA #1133: WaFbcSkipSegments:glk */
+	val = I915_READ(ILK_DPFC_CHICKEN);
+	val &= ~GLK_SKIP_SEG_COUNT_MASK;
+	val = GLK_SKIP_SEG_EN | GLK_SKIP_SEG_COUNT(1);
+	I915_WRITE(ILK_DPFC_CHICKEN, val);
 }
 
 static void i915_pineview_get_mem_freq(struct drm_i915_private *dev_priv)
@@ -8266,6 +8272,8 @@ static void gen8_set_l3sqc_credits(struct drm_i915_private *dev_priv,
 
 static void cnl_init_clock_gating(struct drm_i915_private *dev_priv)
 {
+	u32 val;
+
 	/* This is not an Wa. Enable for better image quality */
 	I915_WRITE(_3D_CHICKEN3,
 		   _MASKED_BIT_ENABLE(_3D_CHICKEN3_AA_LINE_QUALITY_FIX_ENABLE));
@@ -8283,6 +8291,12 @@ static void cnl_init_clock_gating(struct drm_i915_private *dev_priv)
 		I915_WRITE(SLICE_UNIT_LEVEL_CLKGATE,
 			   I915_READ(SLICE_UNIT_LEVEL_CLKGATE) |
 			   SARBUNIT_CLKGATE_DIS);
+
+	/* Display WA #1133: WaFbcSkipSegments:cnl */
+	val = I915_READ(ILK_DPFC_CHICKEN);
+	val &= ~GLK_SKIP_SEG_COUNT_MASK;
+	val = GLK_SKIP_SEG_EN | GLK_SKIP_SEG_COUNT(1);
+	I915_WRITE(ILK_DPFC_CHICKEN, val);
 }
 
 static void kbl_init_clock_gating(struct drm_i915_private *dev_priv)
-- 
2.13.2

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