1. Power management worked fine in previous installations of Ubuntu and Xubuntu but not in Kubuntu,
2. and now again not with openSUSE 13.1 KDE.
3. Have tried xbacklight, KDE Daemon global keyboard shortcuts, command line (echo/ krunner) but still no result.
4. Why did it worked with GNOME/Xfce and does not with KDE?

System Hardware & Software:
Lenovo b570e laptop
Tumbleweed repository up-to-date latest

Can you please confirm that PowerDevil / Power Management is showing as enabled and running in System Settings > Startup & Shutdown > Service Manager?

Yes, I confirm that PowerDevil / Power Management is showing as enabled and running in System Settings > Startup & Shutdown > Service Manager.

By the way, I noticed that Hardware Detection is not running in Load-on-Demand Services in the Service Manager. Although, all my laptop hardware was auto-detected successfully during installation and works fine.

Does the battery applet show the correct charging/battery status of your system?
It sounds like UPower might not be functioning...

It seems to be showing correct battery/charging status, although the battery does seem to charge, and especially discharge, very quickly, presumably due to the unchangeable maximum screen brightness.

By the way, stopping/turning off Power Management from Startup services in Service Manager makes the suspend/resume operation usable when laptop lid is closed. Otherwise, when it (power management) is running, suspend/resume do not work when laptop lid is closed.

I'm assuming it is systemd which is suspending the system - as it has done so in the past.

If you use the options KDE provides, are you able to sleep/hibernate the system?

When KDE Power Management is running as a Startup service:

1. Yes, the system hibernates perfectly.

2. The CPU and battery do not suspend/resume when the laptop lid is closed, only the screen turns off.

Suspend/Resume, Hibernate, Volume/Sound increase/decrease, all those have been working perfectly using both KDE as well as Lenovo/Function hotKeys.

All right, after enough searching, I have found the following solution:

Version 1:
sudo sh -c 'echo 16 > /sys/class/backlight/intel_backlight/brightness'
(where highest value is 976 and lowest is 1)
Source: www.insanelymac.com/forum/topic/282142- ... rightness/

and

Version 2:
echo 5 | sudo tee /sys/class/backlight/intel_backlight/brightness
(where highest value is 976 and lowest is 1)
Source: http://ubuntuforums.org/showthread.php?t=1827810

So, now every time when I start the laptop, I use either of those commands to bring the screen brightness down to my desired. I wish that I could have this permanently/persistently.

I'm afraid i've no idea why Powerdevil isn't acting properly in this case. Can you verify that all desired actions are enabled in the control module?
Also, have you tried using the brightness controls provided by the battery applet to see if they have an effect on the screen brightness?

1. Yes
2. Yes

Did the brightness controls provided by the battery applet work, or did they do nothing? They work through Powerdevil, so if they are working, then it is the automatic triggers which are failing - but if they don't then that indicates that Powerdevil is unable to control the screen brightness at all.

Also, which version of KDE are you using? Depending on the version, and kernel on your system, different techniques are used to change the screen brightness.

Nope, brightness controls provided by battery applet are not working.
KDE 4.12.2 / Tumbleweed repo

Which version of KDE do you have, and which kernel is in use on your system?

Kernel 3.13.-5-17
KDE 4.12.2
Tumbleweed Repository