drm/i915/kbl: Add WaDisableGamClockGating

According to bspec we need to disable gam unit clock gating on
on kbl revids A0 and B0.

References: HSD#2226858, HSD#1944358
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1465309159-30531-14-git-send-email-mika.kuoppala@intel.com
(cherry picked from commit 8aeb7f624fbf8a68a9c67f831d4158a0f80ea920)
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>

2 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index d014b8fabb71..3e16b9dadd92 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6926,6 +6926,7 @@ enum skl_disp_power_wells {
 #define    EDRAM_SETS_IDX(cap)                  (((cap) >> 8) & 0x3)
 
 #define GEN6_UCGCTL1                            _MMIO(0x9400)
+# define GEN6_GAMUNIT_CLOCK_GATE_DISABLE                (1 << 22)
 # define GEN6_EU_TCUNIT_CLOCK_GATE_DISABLE              (1 << 16)
 # define GEN6_BLBUNIT_CLOCK_GATE_DISABLE                (1 << 5)
 # define GEN6_CSUNIT_CLOCK_GATE_DISABLE                 (1 << 7)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 7ae5bfdbf569..3f0f1880d4af 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6722,6 +6722,11 @@ static void kabylake_init_clock_gating(struct drm_device *dev)
         if (IS_KBL_REVID(dev_priv, 0, KBL_REVID_B0))
                 I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) |
                            GEN8_SDEUNIT_CLOCK_GATE_DISABLE);
+
+        /* WaDisableGamClockGating:kbl */
+        if (IS_KBL_REVID(dev_priv, 0, KBL_REVID_B0))
+                I915_WRITE(GEN6_UCGCTL1, I915_READ(GEN6_UCGCTL1) |
+                           GEN6_GAMUNIT_CLOCK_GATE_DISABLE);
 }
 
 static void skylake_init_clock_gating(struct drm_device *dev)