Bug 61979

Summary:	backlight adjustment doesn't work on HP Pavilion m6-1035dx
Product:	DRI	Reporter:	S. Christian Collins <s_chriscollins>
Component:	DRM/Radeon	Assignee:	Default DRI bug account <dri-devel>
Status:	RESOLVED FIXED	QA Contact:
Severity:	normal
Priority:	medium
Version:	unspecified
Hardware:	x86-64 (AMD64)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description S. Christian Collins 2013-03-07 18:03:12 UTC

I am unable to adjust the backlight on my laptop when using the open-source radeon driver, but backlight adjustments to work correctly when using fglrx. xbacklight reports that "No outputs have backlight property".

Now, if I recall correctly, the backlight used to work before I updated the BIOS on this laptop. Prior to the BIOS update, the backlight setting worked in the radeon driver, but was flaky in fglrx. After the update, the backlight setting works correctly in fglrx but not radeon.

Please let me know what information I can provide to help resolve this issue.

Here is my system info:

OS: Kubuntu 12.04 amd64 w/ KDE SC 4.10.1
PC: HP Pavilion m6-1035dx
CPU/GPU: AMD A10-4600M APU with Radeon(tm) HD Graphics
RAM: 6GB DDR3 800 MHz
Linux Kernel: 3.5.0-25-generic
Screen Resolution: 1366 x 768
Xserver: 1.12.3+git20120709+server-1.12-branch.60e0d205

Comment 1 Alex Deucher 2013-03-07 18:13:31 UTC

You are probably using the apci backlight interface which it seems to have been broken by the bios update.  Assuming your laptop uses the on-GPU backlight controller, you should be able to use the standard kernel backlight interface (/sys/class/backlight/) to control it if you have kernel 3.7 or newer.

Comment 2 S. Christian Collins 2013-03-08 18:16:47 UTC

I tested the newer kernel by using a Kubuntu Raring CD, and the backlight adjustments work fine with the Radeon driver. So, I am marking this bug as fixed.

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.