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

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Message-Id: <200810281615.19894.rjw@sisk.pl>
Date:	Tue, 28 Oct 2008 16:15:19 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Thomas Renninger <trenn@...e.de>
Cc:	Andrey Borzenkov <arvidjaar@...l.ru>,
	Len Brown <len.brown@...el.com>, 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 Tuesday, 28 of October 2008, Thomas Renninger wrote:
> On Monday 27 October 2008 17:52:55 Andrey Borzenkov wrote:
> > 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.
> >
> > It is still not in rc2; is it scheduled for 2.6.28 or delayed further?
> 
> Right, it's not there.
> Len, what happened with the:
> "Check for ACPI backlight support otherwise use vendor ACPIdrivers - version 4"
> patches?
> 
> They are pretty essential for video.ko.
> Otherwise graphics devices may get double poked (through vendor_acpi.ko drivers)
> or may register for graphics cards which are not there.

Do you have a pointer to those patches?

Thanks,
Rafael
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