drm/i915/gen9: Implement WaDisableSDEUnitClockGating

v2: Add stepping check for WaDisableSDEUnitClockGating.

Signed-off-by: Nick Hoath <nicholas.hoath@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Rebase.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 2b89aac..874ec9f 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -56,12 +56,14 @@ static void gen9_init_clock_gating(struct drm_device *dev)
 {
        struct drm_i915_private *dev_priv = dev->dev_private;
 
-       /*
-        * WaDisableSDEUnitClockGating:skl
-        * This seems to be a pre-production w/a.
-        */
-       I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) |
-                  GEN8_SDEUNIT_CLOCK_GATE_DISABLE);
+       if (INTEL_REVID(dev) == SKL_REVID_A0) {
+               /*
+                * WaDisableSDEUnitClockGating:skl
+                * This seems to be a pre-production w/a.
+                */
+               I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) |
+                          GEN8_SDEUNIT_CLOCK_GATE_DISABLE);
+       }
 
        /* Wa4x4STCOptimizationDisable:skl */
        I915_WRITE(CACHE_MODE_1,