[Intel-gfx] [PATCH 3/4] drm/i915: Nuke MI_ARB_STATE save/restore

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Originally added in commit 1f84e550a870 ("drm/i915 more registers for
S3 (DSPCLK_GATE_D, CACHE_MODE_0, MI_ARB_STATE)") to fix some underruns.
I suspect that was due to the trickle feed settings getting clobbered
during suspend. We've been disabling trickle feed explicitly since
commit 20f949670f51 ("drm/i915: Disable trickle feed via MI_ARB_STATE
for the gen4") so this magic save/restore should no longer be needed.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h     | 1 -
 drivers/gpu/drm/i915/i915_suspend.c | 6 ------
 2 files changed, 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 3917bb1a6157..cf51246b5402 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -538,7 +538,6 @@ struct intel_gmbus {
 struct i915_suspend_saved_registers {
 	u32 saveDSPARB;
 	u32 saveCACHE_MODE_0;
-	u32 saveMI_ARB_STATE;
 	u32 saveSWF0[16];
 	u32 saveSWF1[16];
 	u32 saveSWF3[3];
diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
index 592c230e6914..34c7d7bccec5 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/drivers/gpu/drm/i915/i915_suspend.c
@@ -66,9 +66,6 @@ int i915_save_state(struct drm_i915_private *dev_priv)
 	if (INTEL_GEN(dev_priv) < 7)
 		dev_priv->regfile.saveCACHE_MODE_0 = I915_READ(CACHE_MODE_0);
 
-	/* Memory Arbitration state */
-	dev_priv->regfile.saveMI_ARB_STATE = I915_READ(MI_ARB_STATE);
-
 	/* Scratch space */
 	if (IS_GEN(dev_priv, 2) && IS_MOBILE(dev_priv)) {
 		for (i = 0; i < 7; i++) {
@@ -107,9 +104,6 @@ int i915_restore_state(struct drm_i915_private *dev_priv)
 		I915_WRITE(CACHE_MODE_0, dev_priv->regfile.saveCACHE_MODE_0 |
 			   0xffff0000);
 
-	/* Memory arbitration state */
-	I915_WRITE(MI_ARB_STATE, dev_priv->regfile.saveMI_ARB_STATE | 0xffff0000);
-
 	/* Scratch space */
 	if (IS_GEN(dev_priv, 2) && IS_MOBILE(dev_priv)) {
 		for (i = 0; i < 7; i++) {
-- 
2.26.2