I can't adjust display brightness

[nata]

I'm using HP Pavilion DV6. After upgrade to Ubuntu 17.10 from 17.04 I can't adjust display brightness. when I press F2|F3 keys icon brightness appears, the controller moves but the brightness doesn't change.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: xorg 1:7.7+19ubuntu3
ProcVersionSignature: Ubuntu 4.13.0-16.19-generic 4.13.4
Uname: Linux 4.13.0-16-generic x86_64
NonfreeKernelModules: wl
.tmp.unity_support_test.0:

ApportVersion: 2.20.7-0ubuntu3
Architecture: amd64
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Thu Oct 19 22:14:51 2017
DistUpgraded: 2017-10-19 21:15:33,861 DEBUG Running PostInstallScript: './xorg_fix_proprietary.py'
DistroCodename: artful
DistroVariant: ubuntu
DkmsStatus:
 bcmwl, 6.30.223.271+bdcom, 4.10.0-37-generic, x86_64: installed
 bcmwl, 6.30.223.271+bdcom, 4.13.0-16-generic, x86_64: installed
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0116] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Hewlett-Packard Company 2nd Generation Core Processor Family Integrated Graphics Controller [103c:3388]
 Advanced Micro Devices, Inc. [AMD/ATI] Whistler [Radeon HD 6730M/6770M/7690M XT] [1002:6740] (rev ff) (prog-if ff)
InstallationDate: Installed on 2017-06-18 (123 days ago)
InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
MachineType: Hewlett-Packard HP Pavilion dv6 Notebook PC
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.13.0-16-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: Upgraded to artful on 2017-10-19 (0 days ago)
dmi.bios.date: 04/25/2011
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: F.13
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: 3388
dmi.board.vendor: Hewlett-Packard
dmi.board.version: 10.25
dmi.chassis.asset.tag: Chassis Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnHewlett-Packard:bvrF.13:bd04/25/2011:svnHewlett-Packard:pnHPPaviliondv6NotebookPC:pvr058F110000244710000610100:rvnHewlett-Packard:rn3388:rvr10.25:cvnHewlett-Packard:ct10:cvrChassisVersion:
dmi.product.family: 103C_5335KV G=N L=CON B=HP S=PAV
dmi.product.name: HP Pavilion dv6 Notebook PC
dmi.product.version: 058F110000244710000610100
dmi.sys.vendor: Hewlett-Packard
version.compiz: compiz 1:0.9.13.1+17.10.20170901-0ubuntu1
version.libdrm2: libdrm2 2.4.83-1
version.libgl1-mesa-dri: libgl1-mesa-dri 17.2.2-0ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx 17.2.2-0ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.19.5-0ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.10.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20170309-0ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-2

[nata (nnbelokon)]

in Unity session, the adjustment works fine

[nata (nnbelokon)]

in X.org session adjustment not working

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Neil Woolford (neil-neilwoolford)]

I found that the brightness controls (via function key or sliders in power management) were changing the values in /sys/class/backlight/acpi_videos0/brightness, but nothing changed in /sys/class/backlight/intel_backlight/brightness.
When I edited the value in /sys/class/backlight/intel_backlight/brightness the display backlight brightness did change.
I also found that the display brightness could be changed in a unity session, (although not by function key).

[Franco (francogpellegrini)]

I have the same problem using an ASPIRE 5750G-9463, using Optimus.

[nata (nnbelokon)]

my laptop also has a graphics card with optimus

[Neil Woolford (neil-neilwoolford)]

This appears to be quite an old issue with Optimus graphics. For me the workaround was to pass specific kernel parameters at boot time to inhibit acpi control of the backlight but allow intel_backlight control
I followed the instructions at https://nisheetlall.wordpress.com/2016/07/12/solved-brightness-fix-in-linux-for-optimus-laptops/ which worked first time for me. Your mileage may of course vary - it happens that I have exactly the same Lenovo Z570 laptop as the author of those instructions.

[nata (nnbelokon)]

Thanks Neil! This method works fine. I hope someday somebody will fix it. In any case, I'll leave it here:

Step 1: Fire a terminal (Obviously)

Step 2: Finding the correct module.

Run the following command:
$ ls /sys/class/backlight/
This should list down two modules:
acpi_video0 and intel_backlight
We need to know which module is exactly controlling the brightness.

Run the below command: (You need to be root)

# tee /sys/class/backlight/acpi_video0/brightness <<< 5
If nothing happens, then intel_backlight is the one handling the brightness settings.

Step 3: Modifying the bootloader.

Next step is modifying the file /etc/default/grub.

(Why modify /etc/default/grub and not /boot/grub/grub.cfg)

# nano /etc/default/grub

Insert the below four lines:

GRUB_CMDLINE_LINUX="acpi_backlight=none"
GRUB_CMDLINE_LINUX="acpi_backlight=video"
GRUB_CMDLINE_LINUX="acpi_backlight=vendor"
GRUB_CMDLINE_LINUX="acpi_backlight=native"
After that save and close the file. (Root access needed)

Run (as root):

# update-grub
Step 4: Reboot your system.

Step 5: Verification

After reboot, fire the terminal one last time and

Run the following command:
$ ls /sys/class/backlight/
12
Voila!!!! acpi_video0 is gone!
Check the fn+Brightness keys or change the brightness via the applet. Brightness controls should work just fine.

Additional info: https://wiki.archlinux.org/index.php/Backlight

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.
Ubuntu 17.10 (artful) reached end-of-life on July 19, 2018.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test. If you then find the bug is still present in the newer Ubuntu version, please add a comment here telling us which new version it is in and change the bug status to Confirmed.