Fwd: [PATCH] i915: Fix bug where screen brightness is not restored

[Linus Torvalds]

Email sent to wrong people/list,

            Linus


---------- Forwarded message ----------
From: Alex Davis <alex14641 at yahoo.com>
Date: Tue, Nov 15, 2011 at 12:42 AM
Subject: [PATCH] i915: Fix bug where screen brightness is not restored
To: "linux-kernel at vger.kernel.org" <linux-kernel at vger.kernel.org>,
"torvalds at linux-foundation.org" <torvalds at linux-foundation.org>


From: Alex Davis<alex14641 at yahoo.com>

This patch fixes an issue where the screen would remain dark when

a key was pressed when the laptop lid was reopened or after the
laptop had gone into power-save mode.

It seems that there are a number of people with different machines
that have this problem:

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/872652
https://launchpad.net/~kamalmostafa/+archive/stuck-backlight
and https://bugs.freedesktop.org/show_bug.cgi?id=41926

This patch is against Linux 3.1

Putting printk's in ./drivers/gpu/drm/i915/intel_panel.c showed that
intel_get_brightness was being called after the panel was disabled,
which caused a 0 to be saved as the value to restore the brightness.
intel_panel_disable_backlight merely sets the brightness to 0. Commenting
out this call allows the correct brightness value to be saved.

Signed-off-by: Alex Davis <alex14641 at yahoo.com>
Tested-by: Kamal Mostafa <kamal at canonical.com>
-----
diff --git a/drivers/gpu/drm/i915/intel_panel.c
b/drivers/gpu/drm/i915/intel_panel.c
index a9e0c7b..6f56676 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -262,8 +262,6 @@ void intel_panel_disable_backlight(struct drm_device *dev)
                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)



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