linux-kernel - Re: ACPI video.c brightness handler conflicts with toshiba

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Date:	Mon, 8 Sep 2008 03:01:24 +0200
From:	Thomas Renninger <trenn@...e.de>
To:	Andrey Borzenkov <arvidjaar@...l.ru>
Cc:	toshiba_acpi@...ebeam.org, linux-acpi@...r.kernel.org,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: ACPI video.c brightness handler conflicts with toshiba_acpi

On Saturday 06 September 2008 09:19:59 am Andrey Borzenkov wrote:
> On Saturday 06 September 2008, Andrey Borzenkov wrote:
> > I have now two different devices that refer to the same hardware:
> >
> > lrwxrwxrwx 1 root root 0 2008-09-06 11:04 acpi_video0 ->
> > ../../devices/virtual/backlight/acpi_video0/ lrwxrwxrwx 1 root root 0
> > 2008-09-06 11:04 toshiba -> ../../devices/virtual/backlight/toshiba/
> >
> > Unfortunately, due to ACPI implementation the acpi_video0 one is much
> > inferior (as it provides only effectively two levels instead of 8);
> > and user level tools are apparently quite confused which one to select.
> >
> > Is there any mechanism that would allow tochiba_acpi to claim brightness
> > for internal LCD screen that video would not attempt to grab it too?
> >
> > Of course manually disabling brightness handling in video is always
> > possible,
>
> Actually it is not. brightness_switch_enabled only disables event handling;
> it still resets actual brightness on loading and creates sysfs files to
> confuse user space.
>
> > still is nice for this to be handled automatically.
It is in latest ACPI test branch queued for 2.6.28.
The problem in bug:
http://bugzilla.kernel.org/show_bug.cgi?id=9614
is another. But the patchset pointed to in comment #43 should fix several, 
also your problem.

If not, please tell me and open a new bug.

Thanks,

       Thomas
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