Bug#703271: linux-image-3.2.0-4-amd64: Fix brightness hotkeys on ASUS UX31A laptop
Package: src:linux
Version: 3.2.39-2
Severity: normal
Tags: upstream
Hi,
Since Linux 3.7, the brightness hotkeys work on this laptop. Initially I
thought that this support was added by a specific plateform driver
commit but after diving in git log it didn't make any sense about why these
hotkeys worked in 3.7 so I started to bisect in order to find the
culprit. Here it is:
>From d627b62ff8d4d36761adbcd90ff143d79c94ab22 Mon Sep 17 00:00:00 2001
From: Lekensteyn <lekensteyn@gmail.com>
Date: Mon, 25 Jun 2012 22:36:24 +0000
Subject: i915: initialize CADL in opregion
This is rather a hack to fix brightness hotkeys on a Clevo laptop. CADL
is not
used anywhere in the driver code at the moment, but it could be used in
BIOS as
is the case with the Clevo laptop.
The Clevo B7130 requires the CADL field to contain at least the ID of
the LCD device. If this field is empty, the ACPI methods that are called
on pressing brightness / display switching hotkeys will not trigger a
notification. As a result, it appears as no hotkey has been pressed.
Reference: https://bugs.freedesktop.org/show_bug.cgi?id=45452
Tested-by: Peter Wu <lekensteyn@gmail.com>
Signed-off-by: Peter Wu <lekensteyn@gmail.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Well, after this result I was puzzled because it seemed to be a
Clevo specific issue but I decided to give it a try and effectively it
gave me the expected behavior, so please could you add it in the next
Wheezy upload?
Also this should probably be forwarded to stable@vger.kernel.org with a
revised commit message stipulating that not only Clevo laptop are
affected, don't know if it is possible though.
Cheers,
Vincent
-- System Information:
Debian Release: 7.0
APT prefers testing
APT policy: (990, 'testing'), (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Kernel: Linux 3.2.40+ (SMP w/4 CPU cores)
Locale: LANG=fr_FR.utf8, LC_CTYPE=fr_FR.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
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