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

From: Kamal Mostafa
Date: Wed Oct 26 2011 - 16:21:51 EST

On Wed, 2011-10-26 at 08:13 -0700, Keith Packard wrote:
> On Tue, 25 Oct 2011 20:19:16 -0700 (PDT), Alex Davis <alex14641@xxxxxxxxx> wrote:
> > 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:
> We have a patch that should land in a 3.1 stable release that should
> resolve this issue; can you test that?
> commit f52c619a590fa75276c07dfcaf380dee53e4ea4c
> Author: Takashi Iwai <tiwai@xxxxxxx>
> Date: Fri Oct 14 11:45:40 2011 +0200
> drm/i915/panel: Always record the backlight level again (but cleverly)

That patch (f52c619a) does not fix the problem on my Dell Studio 1558.

Alex's proposed patch -- removing the intel_panel_set_backlight(dev, 0)
call from intel_panel_disable_backlight -- does fix the problem
completely for me.

Please forgive the silly question, but why does
intel_panel_disable_backlight even want to set the brightness to 0
anyway?... Its only caller is just about to turn off power to the

Is that call to intel_panel_{,actually_}set_backlight(dev, 0) really
necessary or useful on *any* systems?


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