Public bug reported:
On an Asus n55sf, there is an issue with the handling of brightness
adjust keys.
## Severity: consistent annoyance for the target human user
Rationale:
* On this laptop, the most natural way to set LCD brightness (hotkeys) *seems*
to work at first.
* But the user's choice is consistently overriden.
* More precisely: it is overriden whenever, on batteries, there is a pause in
keyboard/mouse activity (e.g. when the user reads text on-screen, or comes back
to the laptop after a minute).
* Caveat: the problem is *not* the laptop dimming the brightness to save
power, this is expected behavior. The problem is, when user provides
events again, brightness is not reverted to value set by hotkeys.
## Context
* X session, it can be Unity or other (e.g. xfce), scenario is the same.
* Bug noticeable when running on batteries (due to automatic brightness change
on idle).
## Expected behavior
* pressing Fn-F5 and Fn-F6 changes the brightness
* pressing Fn-F5 and Fn-F6 show on-screen notification
* on battery after 30 seconds without key/mouse event, backlight is dimmed.
Then, pressing any key or moving mouse restores brigthness at the value set
using keys
## Observed behavior
* pressing Fn-F5 and Fn-F6 changes the brightness -> OK
* pressing Fn-F5 and Fn-F6 *does not* show on-screen notification -> minor
* on battery after 30 seconds without key/mouse event, backlight is dimmed.
Then, pressing any key or moving mouse restores brigthness at the last value
set using software (gnome-control-center, xbacklight, whatever, but *not* the
brightness set using keys) -> bad
## Steps to reproduce
* set backlight to 100% (using gnome-control-center or "xbacklight =100" (usage
scenario : on AC, need bright display)
* unplug AC power to run on battery
* change brightness using Fn-F5, e.g. some value halfway (usage scenario : now
on the move, need to save power)
* count a little more than 30 seconds without touching keyboard/touchpad/mouse,
see brightness reduces to minimum
* press e.g. shift, or move mouse or touchpad
* expected : brightness jumps to halfway (set using hotkeys)
* observed : brightness jumps to maximum (set using software)
## Additional information
* Other keys work: sound volume, wifi toggle, touchpad toggle, sound
play/pause/previous/next/stop
* Some working keys *do* display OSD feedback (at least volume up/down/mute,
touchpad toggle, sound play/pause/previous/next/stop)
* Some working keys do not display OSD feedback (wifi toggle, supend, LCD
toggle, LCD/external display toggle)
* On a different laptop, Asus X77VN, brightness keys do show on-screen
notification with percentage bar, and the bug is never experienced.
Laptop is different model but same brand and software, same packages,
same system and user settings (Unity or xfce, same behaviour).
## Interpretation
* Everything seems consistent with the interpretation that although
brightness hotkeys do work, Ubuntu is never aware of that. So when
Ubuntu changes the brightness, it can not do better than use the value
set using software.
## Workaround
* In gnome control center, uncheck "Dim screen to save power". A quick
test shows that Ubuntu does not change brightness, so user preference
set by hotkey is preserved.
## Other
$ lsb_release -rd
Description: Ubuntu 12.04.1 LTS
Release: 12.04
ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: xorg 1:7.6+12ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-30.48-generic 3.2.27
Uname: Linux 3.2.0-30-generic x86_64
.tmp.unity.support.test.0:
ApportVersion: 2.0.1-0ubuntu12
Architecture: amd64
CompizPlugins:
[core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,workarounds,scale,expo,ezoom]
CompositorRunning: compiz
Date: Mon Aug 27 19:24:46 2012
DistUpgraded: Fresh install
DistroCodename: precise
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes,
GraphicsCard:
Intel Corporation 2nd Generation Core Processor Family Integrated Graphics
Controller [8086:0116] (rev 09) (prog-if 00 [VGA controller])
Subsystem: ASUSTeK Computer Inc. Device [1043:2050]
NVIDIA Corporation GF106 [GeForce GT 555M] [10de:1247] (rev ff) (prog-if ff)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120419)
MachineType: ASUSTeK Computer Inc. N55SF
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-30-generic
root=UUID=31c3e78d-5937-43bd-b4b2-e14e52d2898c ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
XorgConf:
Section "Device"
Identifier "Default Device"
Option "NoLogo" "True"
EndSection
dmi.bios.date: 08/29/2011
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: N55SF.207
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: N55SF
dmi.board.vendor: ASUSTeK Computer Inc.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK Computer Inc.
dmi.chassis.version: 1.0
dmi.modalias:
dmi:bvnAmericanMegatrendsInc.:bvrN55SF.207:bd08/29/2011:svnASUSTeKComputerInc.:pnN55SF:pvr1.0:rvnASUSTeKComputerInc.:rnN55SF:rvr1.0:cvnASUSTeKComputerInc.:ct10:cvr1.0:
dmi.product.name: N55SF
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK Computer Inc.
version.compiz: compiz 1:0.9.7.8-0ubuntu1.4
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.32-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 8.0.3+8.0.2-0ubuntu3.2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 8.0.3+8.0.2-0ubuntu3.2
version.xserver-xorg-core: xserver-xorg-core 2:1.11.4-0ubuntu10.7
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.0-0ubuntu1.2
version.xserver-xorg-video-ati: xserver-xorg-video-ati
1:6.14.99~git20111219.aacbd629-0ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.17.0-1ubuntu4.1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau
1:0.0.16+git20111201+b5534a1-1build2
** Affects: xorg (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug compiz-0.9 precise ubuntu
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You received this bug notification because you are a member of Ubuntu-X,
which is subscribed to xorg in Ubuntu.
https://bugs.launchpad.net/bugs/1042359
Title:
Partially broken brightness hotkey handling.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1042359/+subscriptions
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