Re: [PATCH] fix backlight brightness on intel LVDS panel afterreopening lid

From: Jesse Barnes
Date: Wed Feb 16 2011 - 15:05:31 EST


On Wed, 16 Feb 2011 20:59:35 +0100
Alex Riesen <raa.lkml@xxxxxxxxx> wrote:

> On Wed, Feb 16, 2011 at 20:54, Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx> wrote:
> > On Wed, 16 Feb 2011 20:46:45 +0100
> > Alex Riesen <raa.lkml@xxxxxxxxx> wrote:
> >> > The backlight level on this Dell XPS M1330 reduces every time I reopen
> >> > the lid, and BIOS does not seem to know anything about that (the
> >> > keyboard shortcuts to set backlight brightness cause it to jump to the
> >> > level next to the one set before closing the lid).
> >>
> >> It is this bug, I believe:
> >>
> >> https://bugzilla.kernel.org/show_bug.cgi?id=25072
> >>
> >> I somehow missed it at first, and only noticed after sending the patch.
> >
> > There's also this patch: https://patchwork.kernel.org/patch/499221/.
> > It got things working on my E6510 again at least.
>
> I don't think it is related. I don't have problems switching
> the outputs (frankly, didn't try) and I do have problems
> restoring backlight, very similar to what I had earlier in
> 2.6.37.

Right, but it affects the registration of the backlight and ACPI video
interface as well, so can affect backlight restore on resume. In my
case, without the above patch my backlight wouldn't be restored on
resume, so I'd have to manually echo a value
into /sys/class/backlight/<foo> to get my display back.

--
Jesse Barnes, Intel Open Source Technology Center
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