[Intel-gfx] [PATCH 2/2] drm/i915: don't save/restore backlight hist ctl registers

[Jani Nikula]

This is not used within the driver, and merely saving/restoring these
registers isn't going to do any good anyway. In fact, it's possible it's
actively harmful. Any code enabling the feature should handle this
completely in the regular platform specific enable/disable backlight
functions.

Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h     |  1 -
 drivers/gpu/drm/i915/i915_suspend.c | 16 ++--------------
 drivers/gpu/drm/i915/i915_ums.c     |  2 ++
 3 files changed, 4 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 45ca10937e3e..3f3035ce30e6 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -799,7 +799,6 @@ struct i915_suspend_saved_registers {
 	u32 saveBLC_HIST_CTL;
 	u32 saveBLC_PWM_CTL;
 	u32 saveBLC_PWM_CTL2;
-	u32 saveBLC_HIST_CTL_B;
 	u32 saveBLC_CPU_PWM_CTL;
 	u32 saveBLC_CPU_PWM_CTL2;
 	u32 saveFPB0;
diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
index df2b7f18a679..3c1fccfacac1 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/drivers/gpu/drm/i915/i915_suspend.c
@@ -207,14 +207,8 @@ static void i915_save_display(struct drm_device *dev)
 		dev_priv->regfile.savePP_CONTROL = I915_READ(PCH_PP_CONTROL);
 		if (HAS_PCH_IBX(dev) || HAS_PCH_CPT(dev))
 			dev_priv->regfile.saveLVDS = I915_READ(PCH_LVDS);
-	} else if (IS_VALLEYVIEW(dev)) {
-		dev_priv->regfile.saveBLC_HIST_CTL =
-			I915_READ(VLV_BLC_HIST_CTL(PIPE_A));
-		dev_priv->regfile.saveBLC_HIST_CTL_B =
-			I915_READ(VLV_BLC_HIST_CTL(PIPE_B));
-	} else {
+	} else if (!IS_VALLEYVIEW(dev)) {
 		dev_priv->regfile.savePP_CONTROL = I915_READ(PP_CONTROL);
-		dev_priv->regfile.saveBLC_HIST_CTL = I915_READ(BLC_HIST_CTL);
 		if (IS_MOBILE(dev) && !IS_I830(dev))
 			dev_priv->regfile.saveLVDS = I915_READ(LVDS);
 	}
@@ -262,13 +256,7 @@ static void i915_restore_display(struct drm_device *dev)
 		I915_WRITE(PCH_PP_OFF_DELAYS, dev_priv->regfile.savePP_OFF_DELAYS);
 		I915_WRITE(PCH_PP_DIVISOR, dev_priv->regfile.savePP_DIVISOR);
 		I915_WRITE(PCH_PP_CONTROL, dev_priv->regfile.savePP_CONTROL);
-	} else if (IS_VALLEYVIEW(dev)) {
-		I915_WRITE(VLV_BLC_HIST_CTL(PIPE_A),
-			   dev_priv->regfile.saveBLC_HIST_CTL);
-		I915_WRITE(VLV_BLC_HIST_CTL(PIPE_B),
-			   dev_priv->regfile.saveBLC_HIST_CTL);
-	} else {
-		I915_WRITE(BLC_HIST_CTL, dev_priv->regfile.saveBLC_HIST_CTL);
+	} else if (!IS_VALLEYVIEW(dev)) {
 		I915_WRITE(PP_ON_DELAYS, dev_priv->regfile.savePP_ON_DELAYS);
 		I915_WRITE(PP_OFF_DELAYS, dev_priv->regfile.savePP_OFF_DELAYS);
 		I915_WRITE(PP_DIVISOR, dev_priv->regfile.savePP_DIVISOR);
diff --git a/drivers/gpu/drm/i915/i915_ums.c b/drivers/gpu/drm/i915/i915_ums.c
index 0e03c3610719..d10fe3e9c49f 100644
--- a/drivers/gpu/drm/i915/i915_ums.c
+++ b/drivers/gpu/drm/i915/i915_ums.c
@@ -290,6 +290,7 @@ void i915_save_display_reg(struct drm_device *dev)
 		dev_priv->regfile.saveBLC_PWM_CTL = I915_READ(BLC_PWM_CTL);
 		if (INTEL_INFO(dev)->gen >= 4)
 			dev_priv->regfile.saveBLC_PWM_CTL2 = I915_READ(BLC_PWM_CTL2);
+		dev_priv->regfile.saveBLC_HIST_CTL = I915_READ(BLC_HIST_CTL);
 	}
 
 	return;
@@ -319,6 +320,7 @@ void i915_restore_display_reg(struct drm_device *dev)
 		if (INTEL_INFO(dev)->gen >= 4)
 			I915_WRITE(BLC_PWM_CTL2, dev_priv->regfile.saveBLC_PWM_CTL2);
 		I915_WRITE(BLC_PWM_CTL, dev_priv->regfile.saveBLC_PWM_CTL);
+		I915_WRITE(BLC_HIST_CTL, dev_priv->regfile.saveBLC_HIST_CTL);
 	}
 
 	/* Panel fitter */
-- 
2.1.1