Hi to all
When you are changing in Pisi Linux to opengl 3.1 it could be that your system crashed, here a little solution for it how you can solved it without a new installation .
You have installed Pisi Linux 2.0 with KDE 5 and switch to opengl 3.1
it could be that your System crashed, when you click on apply you become a notice that the opengl version is not compatible with KDE 5.
The default is opengl 2.0.
Now when you have done it and make a reboot you have a black screen after the Login Screen switch there to the tty with CTRL+ALT+F1
Then login there with your Name and give in your Password
after it change to root with sudo su and give in your Root Password
Now give in the following command:
KWIN_COMPOSE=02 kwin –graphicssystem raster –replace &
give in the command so as you see it here with big and little Letters and don’t forget the spaces not.
After it you see a blinking cursor (no name or something) press now
so come you now back after a moment waiting to the normal Desktop.
Reset your settings now to the default (opengl 2.0 ) and make a reboot now.
After the reboot your Pisi Linux System starts normally as ever.
Many thanks for reading here and try Pisi Linux now, before your friend try it.