From: Aaron Lu <aaron.lu@intel.com>
To: Bradley Baetz <bbaetz@gmail.com>, linux-acpi@vger.kernel.org
Subject: Re: Multiple video backlight devices on Dell laptop
Date: Tue, 14 Jan 2014 10:49:40 +0800 [thread overview]
Message-ID: <52D4A5C4.5000405@intel.com> (raw)
In-Reply-To: <CAJrk0Bv5w25vipp8vTmoZEegb-7Va+FLvek=QnTvSfHDFjvroA@mail.gmail.com>
On 01/11/2014 11:22 AM, Bradley Baetz wrote:
> Hi,
>
> I have a Dell Vostro 3560 laptop, with hybrid graphics (intel + radeon).
>
> This exposes 3 backlight devices - acpi_video0, acpi_video1, and
> intel_backlight. Only the intel_backlight/brightness file actually
> changes the backlight. Is this a kernel bug, or should userspace
> 'know' which backlight file to use based on which graphics device is
> active? XFCE picks the first one it finds (acpi_video0), which doesn't
> work.
Solving it from userspace:
You can specify which backlight interface to use by editing /etc/xorg.conf:
Section "Device"
Identifier "Intel Graphics"
Driver "intel"
Option "AccelMethod" "sna"
Option "Backlight" "intel_backlight" # use your backlight that works here
Driver "intel"
BusID "PCI:0:2:0"
EndSection
See https://wiki.archlinux.org/index.php/Backlight
solving it from kernel space:
Since the firmware claims support of win8, you can forget the
acpi_backlight=vendor cmdline option and just use video.use_native_backlight=1.
Hope it helps.
-Aaron
next prev parent reply other threads:[~2014-01-14 2:49 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-11 3:22 Multiple video backlight devices on Dell laptop Bradley Baetz
2014-01-14 2:49 ` Aaron Lu [this message]
2014-01-14 12:34 ` Bradley Baetz
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