drm/i915: Convert backlight_lock to a mutex

Originally the irq safe spinlock was required because of asle
interrupts. But since

commit 91a60f20712179e56b7a6c3d332a5f6f9a54aa11
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Thu Oct 31 18:55:48 2013 +0200

    drm/i915: move opregion asle request handling to a work queue

there's no need for this any more. So switch to the simpler mutex.

v2: Cite the right commit, spotted by Jani.

Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 12 insertions, 18 deletions

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 18784470a760..f17ada3742de 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -538,14 +538,13 @@ static u32 intel_panel_get_backlight(struct intel_connector *connector)
         struct drm_device *dev = connector->base.dev;
         struct drm_i915_private *dev_priv = dev->dev_private;
         u32 val;
-        unsigned long flags;
 
-        spin_lock_irqsave(&dev_priv->backlight_lock, flags);
+        mutex_lock(&dev_priv->backlight_lock);
 
         val = dev_priv->display.get_backlight(connector);
         val = intel_panel_compute_brightness(connector, val);
 
-        spin_unlock_irqrestore(&dev_priv->backlight_lock, flags);
+        mutex_unlock(&dev_priv->backlight_lock);
 
         DRM_DEBUG_DRIVER("get backlight PWM = %d\n", val);
         return val;
@@ -629,12 +628,11 @@ static void intel_panel_set_backlight(struct intel_connector *connector,
         struct intel_panel *panel = &connector->panel;
         enum pipe pipe = intel_get_pipe_from_connector(connector);
         u32 hw_level;
-        unsigned long flags;
 
         if (!panel->backlight.present || pipe == INVALID_PIPE)
                 return;
 
-        spin_lock_irqsave(&dev_priv->backlight_lock, flags);
+        mutex_lock(&dev_priv->backlight_lock);
 
         WARN_ON(panel->backlight.max == 0);
 
@@ -644,7 +642,7 @@ static void intel_panel_set_backlight(struct intel_connector *connector,
         if (panel->backlight.enabled)
                 intel_panel_actually_set_backlight(connector, hw_level);
 
-        spin_unlock_irqrestore(&dev_priv->backlight_lock, flags);
+        mutex_unlock(&dev_priv->backlight_lock);
 }
 
 /* set backlight brightness to level in range [0..max], assuming hw min is
@@ -658,12 +656,11 @@ void intel_panel_set_backlight_acpi(struct intel_connector *connector,
         struct intel_panel *panel = &connector->panel;
         enum pipe pipe = intel_get_pipe_from_connector(connector);
         u32 hw_level;
-        unsigned long flags;
 
         if (!panel->backlight.present || pipe == INVALID_PIPE)
                 return;
 
-        spin_lock_irqsave(&dev_priv->backlight_lock, flags);
+        mutex_lock(&dev_priv->backlight_lock);
 
         WARN_ON(panel->backlight.max == 0);
 
@@ -679,7 +676,7 @@ void intel_panel_set_backlight_acpi(struct intel_connector *connector,
         if (panel->backlight.enabled)
                 intel_panel_actually_set_backlight(connector, hw_level);
 
-        spin_unlock_irqrestore(&dev_priv->backlight_lock, flags);
+        mutex_unlock(&dev_priv->backlight_lock);
 }
 
 static void pch_disable_backlight(struct intel_connector *connector)
@@ -733,7 +730,6 @@ void intel_panel_disable_backlight(struct intel_connector *connector)
         struct drm_i915_private *dev_priv = dev->dev_private;
         struct intel_panel *panel = &connector->panel;
         enum pipe pipe = intel_get_pipe_from_connector(connector);
-        unsigned long flags;
 
         if (!panel->backlight.present || pipe == INVALID_PIPE)
                 return;
@@ -749,14 +745,14 @@ void intel_panel_disable_backlight(struct intel_connector *connector)
                 return;
         }
 
-        spin_lock_irqsave(&dev_priv->backlight_lock, flags);
+        mutex_lock(&dev_priv->backlight_lock);
 
         if (panel->backlight.device)
                 panel->backlight.device->props.power = FB_BLANK_POWERDOWN;
         panel->backlight.enabled = false;
         dev_priv->display.disable_backlight(connector);
 
-        spin_unlock_irqrestore(&dev_priv->backlight_lock, flags);
+        mutex_unlock(&dev_priv->backlight_lock);
 }
 
 static void bdw_enable_backlight(struct intel_connector *connector)
@@ -937,14 +933,13 @@ void intel_panel_enable_backlight(struct intel_connector *connector)
         struct drm_i915_private *dev_priv = dev->dev_private;
         struct intel_panel *panel = &connector->panel;
         enum pipe pipe = intel_get_pipe_from_connector(connector);
-        unsigned long flags;
 
         if (!panel->backlight.present || pipe == INVALID_PIPE)
                 return;
 
         DRM_DEBUG_KMS("pipe %c\n", pipe_name(pipe));
 
-        spin_lock_irqsave(&dev_priv->backlight_lock, flags);
+        mutex_lock(&dev_priv->backlight_lock);
 
         WARN_ON(panel->backlight.max == 0);
 
@@ -962,7 +957,7 @@ void intel_panel_enable_backlight(struct intel_connector *connector)
         if (panel->backlight.device)
                 panel->backlight.device->props.power = FB_BLANK_UNBLANK;
 
-        spin_unlock_irqrestore(&dev_priv->backlight_lock, flags);
+        mutex_unlock(&dev_priv->backlight_lock);
 }
 
 #if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
@@ -1267,7 +1262,6 @@ int intel_panel_setup_backlight(struct drm_connector *connector)
         struct drm_i915_private *dev_priv = dev->dev_private;
         struct intel_connector *intel_connector = to_intel_connector(connector);
         struct intel_panel *panel = &intel_connector->panel;
-        unsigned long flags;
         int ret;
 
         if (!dev_priv->vbt.backlight.present) {
@@ -1280,9 +1274,9 @@ int intel_panel_setup_backlight(struct drm_connector *connector)
         }
 
         /* set level and max in panel struct */
-        spin_lock_irqsave(&dev_priv->backlight_lock, flags);
+        mutex_lock(&dev_priv->backlight_lock);
         ret = dev_priv->display.setup_backlight(intel_connector);
-        spin_unlock_irqrestore(&dev_priv->backlight_lock, flags);
+        mutex_unlock(&dev_priv->backlight_lock);
 
         if (ret) {
                 DRM_DEBUG_KMS("failed to setup backlight for connector %s\n",