drm/i915: ensure single initialization and cleanup of backlight device

commit dc652f90e088798bfa31f496ba994ddadd5d5680 upstream.

Backlight cleanup in the eDP connector destroy callback caused the
backlight device to be removed on some systems that first initialized LVDS
and then attempted to initialize eDP. Prevent multiple backlight
initializations, and ensure backlight cleanup is only done once by moving
it to modeset cleanup.

A small wrinkle is the introduced asymmetry in backlight
setup/cleanup. This could be solved by adding refcounting, but it seems
overkill considering that there should only ever be one backlight device.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=55701
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Tested-by: Peter Verthez <peter.verthez@skynet.be>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
[bwh: Backported to 3.2:
 - Adjust context
 - s/dev_priv->backlight\.device/dev_priv->backlight/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 897ca06f42428f94aed81cb02337a3686b6e9150..cfbb893f4e8f44ab99f4aaa2d45cbee3172eb4b0 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9093,6 +9093,9 @@ void intel_modeset_cleanup(struct drm_device *dev)
        del_timer_sync(&dev_priv->idle_timer);
        cancel_work_sync(&dev_priv->idle_work);
 
+       /* destroy backlight, if any, before the connectors */
+       intel_panel_destroy_backlight(dev);
+
        drm_mode_config_cleanup(dev);
 }
 

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index c8ecaabe7bec1877b8c256cabd254257207ec2be..a07ccab340167155e78453fdc655a71a4b638685 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2274,11 +2274,6 @@ done:
 static void
 intel_dp_destroy(struct drm_connector *connector)
 {
-       struct drm_device *dev = connector->dev;
-
-       if (intel_dpd_is_edp(dev))
-               intel_panel_destroy_backlight(dev);
-
        drm_sysfs_connector_remove(connector);
        drm_connector_cleanup(connector);
        kfree(connector);

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index a8b29fd529e30903ebf658da46f9df3170d3f554..876bac03562db473ac26d4250c8fe9afac5e5f80 100644 (file)
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -553,8 +553,6 @@ static void intel_lvds_destroy(struct drm_connector *connector)
        struct drm_device *dev = connector->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
 
-       intel_panel_destroy_backlight(dev);
-
        if (dev_priv->lid_notifier.notifier_call)
                acpi_lid_notifier_unregister(&dev_priv->lid_notifier);
        drm_sysfs_connector_remove(connector);

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 72b8949031683435a04ee3103424a7e5577375f7..04cb34a37e93cbca8bae0c642309928bd4de8750 100644 (file)
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -361,6 +361,9 @@ int intel_panel_setup_backlight(struct drm_device *dev)
 
        intel_panel_init_backlight(dev);
 
+       if (WARN_ON(dev_priv->backlight))
+               return -ENODEV;
+
        if (dev_priv->int_lvds_connector)
                connector = dev_priv->int_lvds_connector;
        else if (dev_priv->int_edp_connector)
@@ -388,8 +391,10 @@ int intel_panel_setup_backlight(struct drm_device *dev)
 void intel_panel_destroy_backlight(struct drm_device *dev)
 {
        struct drm_i915_private *dev_priv = dev->dev_private;
-       if (dev_priv->backlight)
+       if (dev_priv->backlight) {
                backlight_device_unregister(dev_priv->backlight);
+               dev_priv->backlight = NULL;
+       }
 }
 #else
 int intel_panel_setup_backlight(struct drm_device *dev)