[Intel-gfx] [PATCH 22/23] drm/i915/gen9: Prevent fbc corruption/system hangs with high bw

[Mika Kuoppala]

Set bit 8 in 0x43224 to prevent screen corruption and system
hangs on high memory bandwidth conditions. The same wa also suggest
setting bit 31 on ARB_CTL. According to another workaround we gain
better idle power savings when FBC is enabled.

References: HSD#2137218, HSD#2227171, HSD#2136579
Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h | 2 ++
 drivers/gpu/drm/i915/intel_pm.c | 8 ++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 280d2137f90f..2f3a3960f5f7 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2208,6 +2208,7 @@ enum skl_disp_power_wells {
 #define ILK_DPFC_STATUS		_MMIO(0x43210)
 #define ILK_DPFC_FENCE_YOFF	_MMIO(0x43218)
 #define ILK_DPFC_CHICKEN	_MMIO(0x43224)
+#define   ILK_DPFC_DISABLE_DUMMY0 (1<<8)
 #define ILK_FBC_RT_BASE		_MMIO(0x2128)
 #define   ILK_FBC_RT_VALID	(1<<0)
 #define   SNB_FBC_FRONT_BUFFER	(1<<1)
@@ -6053,6 +6054,7 @@ enum skl_disp_power_wells {
 #define CHICKEN_PIPESL_1(pipe) _MMIO_PIPE(pipe, _CHICKEN_PIPESL_1_A, _CHICKEN_PIPESL_1_B)
 
 #define DISP_ARB_CTL	_MMIO(0x45000)
+#define  DISP_FBC_MEMORY_WAKE		(1<<31)
 #define  DISP_TILE_SURFACE_SWIZZLING	(1<<13)
 #define  DISP_FBC_WM_DIS		(1<<15)
 #define DISP_ARB_CTL2	_MMIO(0x45004)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 62734a16e873..6bd73fb5c4bb 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -68,8 +68,12 @@ static void gen9_init_clock_gating(struct drm_device *dev)
 	I915_WRITE(GEN8_CHICKEN_DCPR_1,
 		   I915_READ(GEN8_CHICKEN_DCPR_1) | MASK_WAKEMEM);
 
-	I915_WRITE(DISP_ARB_CTL,
-		   I915_READ(DISP_ARB_CTL) | DISP_FBC_WM_DIS);
+	I915_WRITE(DISP_ARB_CTL, I915_READ(DISP_ARB_CTL) |
+		   DISP_FBC_WM_DIS |
+		   DISP_FBC_MEMORY_WAKE);
+
+	I915_WRITE(ILK_DPFC_CHICKEN, I915_READ(ILK_DPFC_CHICKEN) |
+		   ILK_DPFC_DISABLE_DUMMY0);
 }
 
 static void bxt_init_clock_gating(struct drm_device *dev)
-- 
2.5.0