From: Ville Syrj?l? <ville.syrjala at linux.intel.com> IVB GT2 has two registers for these things, and both must be written. To add a bit more confusion both Bspec and the W/A database state that WaDisablePSDDualDispatchEnable is only needed for IVB GT1, but the W/A database also says to write even the second GT2 only register. So I don't really know what the right thing here is. Signed-off-by: Ville Syrj?l? <ville.syrjala at linux.intel.com> --- drivers/gpu/drm/i915/intel_pm.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index d18fb39..530eb6b 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -4754,9 +4754,13 @@ static void ivybridge_init_clock_gating(struct drm_device *dev) if (IS_IVB_GT1(dev)) I915_WRITE(GEN7_HALF_SLICE_CHICKEN1, _MASKED_BIT_ENABLE(GEN7_PSD_SINGLE_PORT_DISPATCH_ENABLE)); - else + else { + /* must write both registers */ + I915_WRITE(GEN7_HALF_SLICE_CHICKEN1, + _MASKED_BIT_ENABLE(GEN7_PSD_SINGLE_PORT_DISPATCH_ENABLE)); I915_WRITE(GEN7_HALF_SLICE_CHICKEN1_GT2, _MASKED_BIT_ENABLE(GEN7_PSD_SINGLE_PORT_DISPATCH_ENABLE)); + } /* Apply the WaDisableRHWOOptimizationForRenderHang:ivb workaround. */ I915_WRITE(GEN7_COMMON_SLICE_CHICKEN1, @@ -4772,10 +4776,13 @@ static void ivybridge_init_clock_gating(struct drm_device *dev) if (IS_IVB_GT1(dev)) I915_WRITE(GEN7_ROW_CHICKEN2, _MASKED_BIT_ENABLE(DOP_CLOCK_GATING_DISABLE)); - else + else { + /* must write both registers */ + I915_WRITE(GEN7_ROW_CHICKEN2, + _MASKED_BIT_ENABLE(DOP_CLOCK_GATING_DISABLE)); I915_WRITE(GEN7_ROW_CHICKEN2_GT2, _MASKED_BIT_ENABLE(DOP_CLOCK_GATING_DISABLE)); - + } /* WaForceL3Serialization:ivb */ I915_WRITE(GEN7_L3SQCREG4, I915_READ(GEN7_L3SQCREG4) & -- 1.8.1.5