drm/i915: implement a media hang w/a
Contrary to the other clock gating w/a in GEN6_UCGCTL1, this one is
actually documented in Bspec, vol1g "GT Interface Registers [SNB]",
Section 1.5.1 "UCGCTL1 - Unit Level Clock Gating Control 1".
Supposedly this can prevent hangs on the media ring.
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 2d0dc27..813cc3c 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8880,7 +8880,8 @@
I915_WRITE(GEN6_UCGCTL1,
I915_READ(GEN6_UCGCTL1) |
- GEN6_BLBUNIT_CLOCK_GATE_DISABLE);
+ GEN6_BLBUNIT_CLOCK_GATE_DISABLE |
+ GEN6_CSUNIT_CLOCK_GATE_DISABLE);
/* According to the BSpec vol1g, bit 12 (RCPBUNIT) clock
* gating disable must be set. Failure to set it results in