Adjusting brightness broken after hibernate/suspend

[DieterVDW]

When booting the system normally, the FN+Home (Brightness Up) and FN+End (Brightness down) hotkeys work perfectly.
However, after hibernating or suspending, nothing happens when these keys are pressed.
Also doing: echo "X" > /proc/acpi/video/VID/LCD0/brightness
does not work.
When pressing the hotkeys, I can see the value of this proc entry change correctly though.

I can still change the screen brightness by switching to a terminal using CTRL+ALT+F1, and use the brightness hotkeys there, and then switch back to the X session.

It is like the brightness value is being changed in the system, but the event is not signalled to the screen.
For example if I use the hotkeys to change to brightness value from full to lowest, and then go to the terminal and use the hotkey, the screen immediatly jumps from full brightness to lowest brightness (eg. stored value is applied).
Also if the screen is on full brightness, and I adjust the brightness to lowest and reboot, the system will boot up with low brightness.
Eg. the brightness value I see in /proc/acpi/video/VID/LCD0/brightness is applied to the screen after reboot.

Machine: Lenovo W510

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: linux-image-2.6.32-24-generic 2.6.32-24.38
Regression: Yes
Reproducible: Yes
ProcVersionSignature: Ubuntu 2.6.32-24.38-generic 2.6.32.15+drm33.5
Uname: Linux 2.6.32-24-generic i686
NonfreeKernelModules: nvidia
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
AplayDevices:
 **** List of PLAYBACK Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: HDA Generic [HDA Generic]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: HDA Generic [HDA Generic]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: dvdw 1707 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf2620000 irq 17'
   Mixer name : 'Conexant ID 5069'
   Components : 'HDA:14f15069,17aa218b,00100302'
   Controls : 6
   Simple ctrls : 4
Card1.Amixer.info:
 Card hw:1 'NVidia'/'HDA NVidia at 0xcdefc000 irq 16'
   Mixer name : 'Nvidia ID a'
   Components : 'HDA:10de000a,10de0101,00100100'
   Controls : 0
   Simple ctrls : 0
Card1.Amixer.values:

Card29.Amixer.info:
 Card hw:29 'ThinkPadEC'/'ThinkPad Console Audio Control at EC reg 0x30, fw 6MHT37WW-1.12'
   Mixer name : 'ThinkPad EC 6MHT37WW-1.12'
   Components : ''
   Controls : 1
   Simple ctrls : 1
Card29.Amixer.values:
 Simple mixer control 'Console',0
   Capabilities: pswitch pswitch-joined penum
   Playback channels: Mono
   Mono: Playback [on]
Date: Wed Aug 4 22:51:33 2010
HibernationDevice: RESUME=UUID=e9cae751-6db3-47a6-b967-731f28d4c7cd
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
MachineType: LENOVO 431929G
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-24-generic root=UUID=5ba053dc-ef1e-4c23-889b-bc8464782a47 ro quiet splash resume=UUID=443a06ea-be9c-4e68-872a-16c3633eb88a
ProcEnviron:
 LANGUAGE=en
 LANG=nl_BE.utf8
 SHELL=/bin/bash
RelatedPackageVersions: linux-firmware 1.34.1
SourcePackage: linux
dmi.bios.date: 05/18/2010
dmi.bios.vendor: LENOVO
dmi.bios.version: 6NET57WW (1.20 )
dmi.board.name: 431929G
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr6NET57WW(1.20):bd05/18/2010:svnLENOVO:pn431929G:pvrThinkPadW510:rvnLENOVO:rn431929G:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 431929G
dmi.product.version: ThinkPad W510
dmi.sys.vendor: LENOVO

[DieterVDW (dietervdw)]

To reproduce:
1. Boot normally, test brightness hotkeys => working
2. Hibernate
3. Resume
4. Test brightness hotkeys => nothing happens

[DieterVDW (dietervdw)]

After some more research, found the following webpage:
http://www.thinkwiki.org/wiki/Category:W510

Solution:
Add following line to NVidia Device section in xorg.conf:
Option "RegistryDwords" "EnableBrightnessControl=1"

[Martin Spacek (mspacek)]

Dieter, I also have a Thinkpad W510, with the nvidia driver, in maverick now, and outside of a terminal, I've never gotten the brightness keys to work without the "EnableBrightnessControl=1" workaround in xorg.conf, whether before or after a hibernate/suspend. Are you sure this was actually the case? If you remove that line from your xorg.conf and reboot, do your brightness keys work? If so, what version of the nvidia blob are you using? I'm on the latest from the official repo, 260.19.06.

I'll mark this as a duplicate of the main LP Bug #562005 . I guess it would be best to respond there.

[Thomas Weber (th-we)]

This also affects me on a Thinkpad T61 with an "Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller" and Trusty, so it does not seem to be Nvidia specific. As Dieter wrote, the brightness keys *do* work before hibernate and continue to work if switching to a terminal with e.g. Ctrl-Alt-F1.

[JMR (jmr5875)]

I have the exact same issue as the reporter with my Thinkpad X1 Carbon, which has a Intel card. So it's not Nvidia specifc. The terminal workaround works as well here.