Re: [Regression] Laptop screen dark when lid closed and reopened.with 3.1

[Alex Davis]

At the request of Kamal Mostafa, an Ubuntu kernel developer, I am resubmitting this patch which fixes my backlight issue.
It seem 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

The goal here is to either get the patch included, or provoke a discussion of the issue.

This patch is against 3.1 rc8 with Keith Packard's drm-intel-fixes merged in.

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@xxxxxxxxx>
Tested-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>


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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