drm/i915: gen7: implement rczunit workaround

This is yet another workaround related to clock gating which we need on Ivy Bridge. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41353 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44610 Tested-by: Eugeni Dodonov <eugeni.dodonov@intel.com> Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com> Signed-off-by: Kenneth Graunke <kenneth@whitecape.org> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
git-mirror · Feb 10, 2012 · eae66b5 · eae66b5
1 parent 8597559
commit eae66b5
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diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
@@ -3618,6 +3618,7 @@
 #define    GT_FIFO_NUM_RESERVED_ENTRIES		20
 
 #define GEN6_UCGCTL2				0x9404
+# define GEN6_RCZUNIT_CLOCK_GATE_DISABLE		(1 << 13)
 # define GEN6_RCPBUNIT_CLOCK_GATE_DISABLE		(1 << 12)
 # define GEN6_RCCUNIT_CLOCK_GATE_DISABLE		(1 << 11)
 

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
@@ -8461,6 +8461,11 @@ static void ivybridge_init_clock_gating(struct drm_device *dev)
 	I915_WRITE(WM2_LP_ILK, 0);
 	I915_WRITE(WM1_LP_ILK, 0);
 
+	/* According to the spec, bit 13 (RCZUNIT) must be set on IVB.
+	 * This implements the WaDisableRCZUnitClockGating workaround.
+	 */
+	I915_WRITE(GEN6_UCGCTL2, GEN6_RCZUNIT_CLOCK_GATE_DISABLE);
+
 	I915_WRITE(ILK_DSPCLK_GATE, IVB_VRHUNIT_CLK_GATE);
 
 	I915_WRITE(IVB_CHICKEN3,