An odd problem I’m experiencing in KDE 4.2 / openSUSE 11.1:
When I create a new profile in PowerDevil (under Personal Settings > Advanced > PowerManagement), I’m unable to change the level of screen brightness. This is a bit annoying since it is always set automatically to only about 80% of screen brightness. (Also, I’m unable to adjust the level of existing profiles, but some of them like ‘Performance’ are set to 100%).
However, I’m able to adjust the level manually either through the Battery Monitory Widget of through KRunner (although the latter only allows me to dim the screen, not raise the level).
Is this a bug in PowerDevil?
Try deleting all powerdevil config files here
.kde4/share/config
logout and back in
try setting it up again
Thanks for the tip, caf4926.
I finally got around to this issue today and tried deleting all powerdevil files in .kde4/share/config. Unfortunately didn’t help, I’m still stuck being unable to set the screen brightness. 
Will file a bug report.:\
Cheers,
homoludens
See here - Edit Profiles - Powersave
http://thumbnails.imagebam.com/3949/ddbaf139483774.gif](http://www.imagebam.com/image/ddbaf139483774/)
Notice the tabs (though they don’t look like tabs) lower section of the screen center/left. I just clicked ‘Screen’
You can move the brightness slider.
Are you saying you don’t have this or it just doesn’t work?
No, no, I do have those tabs and the slider, it’s just that I can’t move it.
Particularly annoying, as I described earlier, when you create a new profile: the screen brightness there is, for whatever reason, preset to only 80% of possible output, and I can’t adjust it … :’(
You don’t have powersave still installed do you?
These are my System Capabilities, as detected by PowerDevil:
http://thumbnails16.imagebam.com/3952/15ac9b39517925.gif](http://www.imagebam.com/image/15ac9b39517925)
This, by the way, is a screenshot of the profile > screen settings window. Probably impossible to see, but the slider is stuck / can’t be moved:
http://thumbnails11.imagebam.com/3952/13e89239517926.gif](http://www.imagebam.com/image/13e89239517926)
PS: Thanks for the link to imagebam, very convenient website! 
The slider is stuck in all profiles is it?
Are you using the kde42’ repo’s?
do:
kde4-config -v
Have you tried a creating new user and see how it behaves there?
Yes, the slider is stuck in all profiles.
Here’s my KDE 4 output:
homoludens@linux-chameleon:~> kde4-config -v
Qt: 4.4.3
KDE: 4.2.4 (KDE 4.2.4) "release 2"
kde4-config: 1.0
The KDE 4.2 repos are activated in my laptop.
I’ve been wondering whether the problem somehow has to do with whether or not one activates the setting “Let PowerDevil manage screen powersaving”, but apparently it doesn’t matter whether I switch it on or off.
FWIW, I can report the same problem re screen brightness slider (ThnikPad Z60m with KDE 4.2.4). I haven’t worried about it because I can still adjust brightness via keyboard.
This is me making the adjustments
carl4926 - Powerdevil Slider
This is me being unable to make the adjustments …
http://thumbnails16.imagebam.com/3977/89dcb239768243.gif](http://www.imagebam.com/image/89dcb239768243/)
deano_ferrari, thanks for the post. I wonder what the difference is between your installation and mine on the one hand, and caf4926’s installation on the other … I assume we’re all running openSUSE 11.1 / KDE 4.2? Are you using a multilanguage environment and/or CJK languages?
Well my sig does show me as kde4.3 beta, which is correct!
But 4.2 was fine for me also only a short time ago.
What about if you create a new user, did you try that?
I just wonder if its a hardware related (kernel support) issue. Now, I don’t pretend to know a lot about this, but I’ve had had a quick look at /proc/acpi/video/ and I have and LCD0 directory with ‘brightness’ file contained. I get:
cat /proc/acpi/video/VID1/LCD0/brightness
<not supported>
Could this be the problem?
There is a KDE command line tool called solid-powermanagement which can be used to query various power management settings:
dean@linux:~> solid-powermanagement --commands
Syntax:
solid-powermanagement query (suspend|scheme|cpufreq)
# List a particular set of information regarding power management.
# - If the ‘suspend’ option is specified, give the list of suspend
# methods supported by the system
# - If the ‘scheme’ option is specified, give the list of
# supported power management schemes supported by this system
# - If the ‘cpufreq’ option is specified, give the list of
# supported CPU frequency policies
solid-powermanagement set (scheme|cpufreq) ‘value’
# Set power management options of the system.
# - If the ‘scheme’ option is specified, the power management
# scheme set corresponds to ‘value’
# - If the ‘cpufreq’ option is specified, the CPU frequency policy
# set corresponds to ‘value’
solid-powermanagement suspend ‘method’
# Suspend the computer using the given ‘method’.
solid-powermanagement brightness (set|get) ‘value’
# Set and get brightness options of the system.
# - If the ‘set’ option is specified, the brightness is
# set to ‘value’ (as a percentage)
# - If the ‘get’ option is specified, the current brightness
# is returned (as a percentage)’
However, I get strange errors if I try to set or get brightness values. For example:
dean@linux:~> solid-powermanagement brightness set 50
Setting brightness to 50%
Fatal Error: Accessed global static ‘KCatalogStaticData *catalogStaticData()’ after destruction. Defined at /usr/src/packages/BUILD/kdelibs-4.2.4/kdecore/localization/kcatalog.cpp:72
Aborted
Thanks for the interesting posts, deano_ferrari.
(1) I assume the file on my laptop that corresponds to yours in /proc/acpi/video is /proc/acpi/video/GRFX/LCD1. ‘cat brightness’ yields the same value: <not supported>.
(2) I also get error messages when reading / setting screen brightness using the solid-powermanagement command. However, despite the ‘aborted’ message, the brightness level is actually adjusted:
homoludens@linux-chameleon:/proc/acpi/video/GRFX/LCD1> solid-powermanagement brightness get
Brightness is 80%
Fatal Error: Accessed global static 'KCatalogStaticData *catalogStaticData()' after destruction. Defined at /usr/src/packages/BUILD/kdelibs-4.2.4/kdecore/localization/kcatalog.cpp:72
Aborted
/* I was correct in my assumption that my screen brightness level is stuck at 80%! ;) */
homoludens@linux-chameleon:/proc/acpi/video/GRFX/LCD1> solid-powermanagement brightness set 30
Setting brightness to 30%
Fatal Error: Accessed global static 'KCatalogStaticData *catalogStaticData()' after destruction. Defined at /usr/src/packages/BUILD/kdelibs-4.2.4/kdecore/localization/kcatalog.cpp:72
Aborted
homoludens@linux-chameleon:/proc/acpi/video/GRFX/LCD1> solid-powermanagement brightness set 100
Setting brightness to 100%
Fatal Error: Accessed global static 'KCatalogStaticData *catalogStaticData()' after destruction. Defined at /usr/src/packages/BUILD/kdelibs-4.2.4/kdecore/localization/kcatalog.cpp:72
Aborted
Does this information help in any way?
Do you have kde3 or gnome installed also?
Do you have kde3 or gnome installed also?
Yes, I have KDE 3 as well (although rarely used now).
(2) I also get error messages when reading / setting screen brightness using the solid-powermanagement command. However, despite the ‘aborted’ message, the brightness level is actually adjusted:
How curious. (Mine does not get adjusted, although it says it does).
What I do now know, from a search on ‘powerdevil’, ‘solid-powermanagement’, ‘screen brightness’, (and similar terms), is that there are quite a number KDE4 bug reports around concerning the issue -specific to particular hardware.
