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

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Message-Id: <200810281922.20490.arvidjaar@mail.ru>
Date:	Tue, 28 Oct 2008 19:22:12 +0300
From:	Andrey Borzenkov <arvidjaar@...l.ru>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	Thomas Renninger <trenn@...e.de>, 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 October 2008, Rafael J. Wysocki wrote:
> 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?
> 

So far I am running with these commits from git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-acpi-2.6:

commit f43d728731c691772ddc29e50d25c68a859935b5
Author: Thomas Renninger <trenn@...e.de>
Date:   Fri Aug 1 17:37:55 2008 +0200

    Check for ACPI backlight support otherwise use vendor ACPI drivers


commit ad9ed8385ed6ec5be8da7094db911c824258ceec
Author: Thomas Renninger <trenn@...e.de>
Date:   Fri Aug 1 17:37:54 2008 +0200

    ACPI: video: Ignore devices that aren't present in hardware

I have been waiting for in-tree inclusion to submit patches for
toshiba_acpi against stable base.


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