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

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Date:	Mon, 8 Sep 2008 21:24:29 +0400
From:	Andrey Borzenkov <arvidjaar@...l.ru>
To:	Thomas Renninger <trenn@...e.de>, Zhang Rui <rui.zhang@...el.com>
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 Monday 08 September 2008, Thomas Renninger wrote:
> 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.
> 

It was exactly the right one. I'll get a look at adding proper detection
for Toshiba HCI systems. Thank you!

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