[Intel-gfx] [PATCH] drm/i915: Set two chicken bits implicated in missed IRQs on Ivybridge.

[Eric Anholt]

They don't fix our problems alone, but we're told to set them.

Signed-off-by: Eric Anholt <eric at anholt.net>
---

I think this is -next material, since it's not clearly fixing a bug.

 drivers/gpu/drm/i915/i915_reg.h      |    4 ++++
 drivers/gpu/drm/i915/intel_display.c |    4 ++++
 2 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 9d15474..9a97535 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2883,6 +2883,10 @@
 #define   ILK_DPFC_DIS1		(1<<8)
 #define   ILK_DPFC_DIS2		(1<<9)
 
+#define IVB_CHICKEN3	0x4200c
+# define CHICKEN3_DGMG_REQ_OUT_FIX_DISABLE	(1 << 5)
+# define CHICKEN3_DGMG_DONE_FIX_DISABLE		(1 << 2)
+
 #define DISP_ARB_CTL	0x45000
 #define  DISP_TILE_SURFACE_SWIZZLING	(1<<13)
 #define  DISP_FBC_WM_DIS		(1<<15)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 8a61b81..1fe0c67 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8252,6 +8252,10 @@ static void ivybridge_init_clock_gating(struct drm_device *dev)
 
 	I915_WRITE(ILK_DSPCLK_GATE, IVB_VRHUNIT_CLK_GATE);
 
+	I915_WRITE(IVB_CHICKEN3,
+		   CHICKEN3_DGMG_REQ_OUT_FIX_DISABLE |
+		   CHICKEN3_DGMG_DONE_FIX_DISABLE);
+
 	for_each_pipe(pipe) {
 		I915_WRITE(DSPCNTR(pipe),
 			   I915_READ(DSPCNTR(pipe)) |
-- 
1.7.7.3