drm/i915: implement w/a for incorrect guarband clipping
According to Bsepc, this should be set by default, but isn't. See vo1c.4
"Render Engine Command Streamer", Section 1.1.14.3 "3D_CHICKEN3"
Bspec also says that we always need to set all mask bits.
v2: Add comment about the mask bits wtf.
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 813cc3c..1a6bb61 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8897,6 +8897,10 @@
GEN6_RCPBUNIT_CLOCK_GATE_DISABLE |
GEN6_RCCUNIT_CLOCK_GATE_DISABLE);
+ /* Bspec says we need to always set all mask bits. */
+ I915_WRITE(_3D_CHICKEN, (0xFFFF << 16) |
+ _3D_CHICKEN_SF_DISABLE_FASTCLIP_CULL);
+
/*
* According to the spec the following bits should be
* set in order to enable memory self-refresh and fbc: