Hey guys in this post i'm gonna show you how to stop flickering in kubuntu 15.04. So open the terminal and add the following command in terminal.
sudo nano /etc/X11/xorg.conf
and add the following lines in the file
Section "Device"
Identifier "Configured Video Device"
Driver "radeon"
EndSection
sudo nano /etc/X11/xorg.conf
and add the following lines in the file
Section "Device"
Identifier "Configured Video Device"
Driver "radeon"
EndSection
thats it.