Bug 290734

Summary:	unable to change brightness in sony vaio cw
Product:	[Unmaintained] solid	Reporter:	black_painkiller
Component:	powermanagement	Assignee:	Dario Freddi <drf>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	ossi
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Ubuntu
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description black_painkiller 2012-01-05 19:32:05 UTC

Version:           unspecified (using Devel) 
OS:                Linux

I try to change brightnes using Fn keys or the standard Battery Monitor Applet in panel but it doesnt work. 
With Fn keys, nothing appeared on screen, and doesnt work
With the applet, the slider appear on the screen, but brightness remains the same.

I'm using KDE 4.7.95 (4.8rc1) in Ubuntu 12.04. Note that on Unity and Gnome3 setting the brightness always worked. 
It also worked without problem in previous version of KDE (don't remember if 4.6 or 4.7).

qdbusviewer:
org/kde/Solid/PowerManagement.setBrightness show the slider on screen, but don't work.

on terminal:
echo 50 >  /sys/class/backlight/nv_backlight/brightness

lscpi:
01:00.0 VGA compatible controller: nVidia Corporation GT216 [GeForce GT 230M] (rev a2) (prog-if 00 [VGA controller])

Using nouveau driver. Kernel 3.2.

Hope this will help, it's my first bug report, it's a really annoying problem to always set brightness by mean of a terminal. The default brighness is set to maximum and it burns my eyes.

Cheers


Reproducible: Didn't try

Steps to Reproduce:
Every time

Actual Results:  
max brightness

Expected Results:  
configurable brightness

Comment 1 black_painkiller 2012-01-07 11:59:59 UTC

Update:
the previous problem happened on Ubuntu with installed KDE, that is selecting KDE from Lightdm.
I tried to use KDM and the problem is solved.

I guess that KDM starts some deamon that provide brightness controll.

I think this must be set by some kde deamon starting with kde session, not KDM!

Comment 2 Dario Freddi 2012-01-07 15:35:02 UTC

The bug is definitely upstream then, and should be fixed in LightDM. I see two possible causes:

1. LightDM doesn't interact properly with consolekit - this probably leads to several other issues.
2. LightDM does not instruct KDE to start a full session.

Anyway, KDM doesn't start any daemon related to brightness control, which is handled in kded4.

Comment 3 black_painkiller 2012-01-07 15:47:03 UTC

The problem appears also with Gdm.

Comment 4 Dario Freddi 2012-01-07 17:44:47 UTC

Same as above, it probably needs a fix on their side. Ossi, do you have any pointers for this issue?