[ 3.5.y.z extended stable ] Patch "drm/i915: ensure single initialization and cleanup of" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    drm/i915: ensure single initialization and cleanup of

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From a23402d4da4041f930a6495102a26de9c574c442 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula at intel.com>
Date: Fri, 12 Apr 2013 15:18:38 +0300
Subject: [PATCH] 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 at intel.com>
Tested-by: Peter Verthez <peter.verthez at skynet.be>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
[ luis: Backported to 3.5 (based on bwh's backport to 3.2):
  - Adjust context
  - - s/dev_priv->backlight\.device/dev_priv->backlight/ ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/gpu/drm/i915/intel_display.c | 3 +++
 drivers/gpu/drm/i915/intel_dp.c      | 5 -----
 drivers/gpu/drm/i915/intel_lvds.c    | 2 --
 drivers/gpu/drm/i915/intel_panel.c   | 7 ++++++-
 4 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 2ec0617..290d89d 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7146,6 +7146,9 @@ 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 0abe7ec..b6f6963 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2336,11 +2336,6 @@ 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 2aff20f..6d6bf60 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -559,8 +559,6 @@ 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 2a1625d..d5fd67e 100644
--- 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)
@@ -389,8 +392,10 @@ 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)
--
1.8.1.2