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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 6fa150e7eb467027ea73db6b73c6df1fb5a503d4..f9ac54a2dc1e22fe2b919a3ed7ed181595600618 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9256,6 +9256,9 @@ void intel_modeset_cleanup(struct drm_device *dev)
        /* flush any delayed tasks or pending work */
        flush_scheduled_work();
 
+       /* destroy backlight, if any, before the connectors */
+       intel_panel_destroy_backlight(dev);
+
        drm_mode_config_cleanup(dev);
 
        intel_cleanup_overlay(dev);

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 8fc93f90a7cdf9262d52186697b09ca84879b137..b8e17e564013164cff792b4271cf40c3985e564d 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2538,17 +2538,14 @@ done:
 static void
 intel_dp_destroy(struct drm_connector *connector)
 {
-       struct drm_device *dev = connector->dev;
        struct intel_dp *intel_dp = intel_attached_dp(connector);
        struct intel_connector *intel_connector = to_intel_connector(connector);
 
        if (!IS_ERR_OR_NULL(intel_connector->edid))
                kfree(intel_connector->edid);
 
-       if (is_edp(intel_dp)) {
-               intel_panel_destroy_backlight(dev);
+       if (is_edp(intel_dp))
                intel_panel_fini(&intel_connector->panel);
-       }
 
        drm_sysfs_connector_remove(connector);
        drm_connector_cleanup(connector);

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 65893b053730c7cc0b6a9ca6821f6d21800fcfcc..e0d69852b0dd3c09794c7cffd4cc5adab4c4cf76 100644 (file)
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -618,7 +618,6 @@ static void intel_lvds_destroy(struct drm_connector *connector)
        if (!IS_ERR_OR_NULL(lvds_connector->base.edid))
                kfree(lvds_connector->base.edid);
 
-       intel_panel_destroy_backlight(connector->dev);
        intel_panel_fini(&lvds_connector->base.panel);
 
        drm_sysfs_connector_remove(connector);

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index bee8cb6108a7d44883286ef4b35bb6d7f8713a0f..94d895b665d5d7400b32cb17ad46333505ce004a 100644 (file)
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -422,6 +422,9 @@ int intel_panel_setup_backlight(struct drm_connector *connector)
 
        intel_panel_init_backlight(dev);
 
+       if (WARN_ON(dev_priv->backlight))
+               return -ENODEV;
+
        memset(&props, 0, sizeof(props));
        props.type = BACKLIGHT_RAW;
        props.max_brightness = _intel_panel_get_max_backlight(dev);
@@ -447,8 +450,10 @@ int intel_panel_setup_backlight(struct drm_connector *connector)
 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_connector *connector)