5 files changed, 39 insertions, 8 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index aac1bf332f75..972e08e4e054 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -332,6 +332,7 @@ typedef struct drm_i915_private {
 
         /* LVDS info */
         int backlight_level;  /* restore backlight to this value */
+        bool backlight_enabled;
         struct drm_display_mode *panel_fixed_mode;
         struct drm_display_mode *lfp_lvds_vbt_mode; /* if any */
         struct drm_display_mode *sdvo_lvds_vbt_mode; /* if any */
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index f4d1797350f6..bc829bbc14c8 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5802,6 +5802,8 @@ static void intel_setup_outputs(struct drm_device *dev)
                 encoder->base.possible_clones =
                         intel_encoder_clones(dev, encoder->clone_mask);
         }
+
+        intel_panel_setup_backlight(dev);
 }
 
 static void intel_user_framebuffer_destroy(struct drm_framebuffer *fb)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index d782ad9fd6db..74db2557d644 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -257,6 +257,9 @@ extern void intel_pch_panel_fitting(struct drm_device *dev,
 extern u32 intel_panel_get_max_backlight(struct drm_device *dev);
 extern u32 intel_panel_get_backlight(struct drm_device *dev);
 extern void intel_panel_set_backlight(struct drm_device *dev, u32 level);
+extern void intel_panel_setup_backlight(struct drm_device *dev);
+extern void intel_panel_enable_backlight(struct drm_device *dev);
+extern void intel_panel_disable_backlight(struct drm_device *dev);
 
 extern void intel_crtc_load_lut(struct drm_crtc *crtc);
 extern void intel_encoder_prepare (struct drm_encoder *encoder);
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index aa2307080be2..4e7dcb330dad 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -106,7 +106,7 @@ static void intel_lvds_enable(struct intel_lvds *intel_lvds)
         I915_WRITE(ctl_reg, I915_READ(ctl_reg) | POWER_TARGET_ON);
         POSTING_READ(lvds_reg);
 
-        intel_panel_set_backlight(dev, dev_priv->backlight_level);
+        intel_panel_enable_backlight(dev);
 }
 
 static void intel_lvds_disable(struct intel_lvds *intel_lvds)
@@ -123,8 +123,7 @@ static void intel_lvds_disable(struct intel_lvds *intel_lvds)
                 lvds_reg = LVDS;
         }
 
-        dev_priv->backlight_level = intel_panel_get_backlight(dev);
-        intel_panel_set_backlight(dev, 0);
+        intel_panel_disable_backlight(dev);
 
         I915_WRITE(ctl_reg, I915_READ(ctl_reg) & ~POWER_TARGET_ON);
 
@@ -398,8 +397,6 @@ static void intel_lvds_prepare(struct drm_encoder *encoder)
         struct drm_i915_private *dev_priv = dev->dev_private;
         struct intel_lvds *intel_lvds = to_intel_lvds(encoder);
 
-        dev_priv->backlight_level = intel_panel_get_backlight(dev);
-
         /* We try to do the minimum that is necessary in order to unlock
          * the registers for mode setting.
          *
@@ -430,9 +427,6 @@ static void intel_lvds_commit(struct drm_encoder *encoder)
         struct drm_i915_private *dev_priv = dev->dev_private;
         struct intel_lvds *intel_lvds = to_intel_lvds(encoder);
 
-        if (dev_priv->backlight_level == 0)
-                dev_priv->backlight_level = intel_panel_get_max_backlight(dev);
-
         /* Undo any unlocking done in prepare to prevent accidental
          * adjustment of the registers.
          */
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 7350ec2515c6..e00d200df3db 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -250,3 +250,34 @@ void intel_panel_set_backlight(struct drm_device *dev, u32 level)
                 tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK;
         I915_WRITE(BLC_PWM_CTL, tmp | level);
 }
+
+void intel_panel_disable_backlight(struct drm_device *dev)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+
+        if (dev_priv->backlight_enabled) {
+                dev_priv->backlight_level = intel_panel_get_backlight(dev);
+                dev_priv->backlight_enabled = false;
+        }
+
+        intel_panel_set_backlight(dev, 0);
+}
+
+void intel_panel_enable_backlight(struct drm_device *dev)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+
+        if (dev_priv->backlight_level == 0)
+                dev_priv->backlight_level = intel_panel_get_max_backlight(dev);
+
+        intel_panel_set_backlight(dev, dev_priv->backlight_level);
+        dev_priv->backlight_enabled = true;
+}
+
+void intel_panel_setup_backlight(struct drm_device *dev)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+
+        dev_priv->backlight_level = intel_panel_get_max_backlight(dev);
+        dev_priv->backlight_enabled = dev_priv->backlight_level != 0;
+}