[HP Pavilion 15] Brightness cannot be adjusted with the radeon driver

[Po-Hsu Lin]

CID: 201306-13641 HP Pavilion 15

Steps:
1. Install 12.04.3 + updates (3.8.0-34), boot to desktop
2. Try to adjust screen brightness by the hotkeys
3. Try to adjust screen brightness by the "Brightness and Lock" applet

Expected Results:
* Brightness could be adjusted.

Actual Results:
* The birghtness level indicator will change, but the brightness won't.

Workaround:
Install the proprietart fglrx driver, however, bug 1264259 will make both of these two bugs become blockers

Debugging information:
$ ls /sys/class/backlight
acpi_video0 acpi_video1 radeon_bl0

$ grep -r . /proc/acpi
/proc/acpi/button/lid/LID/state:state: open
grep: /proc/acpi/event: Permission denied
/proc/acpi/wakeup:Device S-state Status Sysfs node
/proc/acpi/wakeup:PB5 S5 *disabled pci:0000:00:05.0
/proc/acpi/wakeup:XPDV S5 *enabled pci:0000:03:00.0
/proc/acpi/wakeup:OHC1 S3 *enabled pci:0000:00:12.0
/proc/acpi/wakeup:OHC2 S3 *enabled pci:0000:00:13.0
/proc/acpi/wakeup:EHC1 S3 *enabled pci:0000:00:12.2
/proc/acpi/wakeup:EHC2 S3 *enabled pci:0000:00:13.2
/proc/acpi/wakeup:XHC0 S3 *enabled pci:0000:00:10.0
/proc/acpi/wakeup:KBC0 S3 *enabled pnp:00:06
/proc/acpi/wakeup:PS2M S3 *disabled pnp:00:07

$ dmesg | grep 'ACPI: Video'
[ 9.618209] ACPI: Video Device [VGA] (multi-head: yes rom: no post: no)
[ 9.619751] ACPI: Video Device [VGA1] (multi-head: yes rom: no post: no)

$ cat /proc/version
Linux version 3.8.0-34-generic (buildd@toyol) (gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) ) #49~precise1-Ubuntu SMP Wed Nov 13 18:05:00 UTC 2013

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: xserver-xorg-video-radeon-lts-raring 1:7.1.0-0ubuntu2~precise1
ProcVersionSignature: Ubuntu 3.8.0-34.49~precise1-generic 3.8.13.12
Uname: Linux 3.8.0-34-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: amd64
Date: Thu Dec 26 05:34:31 2013
InstallationMedia: Ubuntu 12.04.3 LTS "Precise Pangolin" - Release amd64 (20130820.1)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: xserver-xorg-video-ati-lts-raring
UpgradeStatus: No upgrade log present (probably fresh install)

[Po-Hsu Lin (cypressyew)]

With "acpi_backlight=vendor" added into grub,
the screen brightness could be adjusted correctly.

Debugging information:
$ ls /sys/class/backlight
radeon_bl0

[Timo Aaltonen (tjaalton)]

does this work with 15.10 or xenial?

[Po-Hsu Lin (cypressyew)]

Verified on 201306-13641 with Xenial image, brightness control works as expected.

[Angelo Jillissen (angelojillissen)]

Thanks for reply broo https://cracksreg.com/