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

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Date:	Sat, 6 Sep 2008 11:19:59 +0400
From:	Andrey Borzenkov <arvidjaar@...l.ru>
To:	toshiba_acpi@...ebeam.org
Cc:	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, 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.
> 



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