KDE and Kubuntu Troubleshooting Guide

Login Splash Screen Loops on Login Attempt

Your password is correct, but when you attempt to log in from the graphical splash screen login you see KDE start to load, then goes right back to the login screen.

Sometimes after mucking around as sudo you lost permissions on one or more critical file in your home directory. Try:

sudo chown username:username .Xauthority

Replace "username" with your specific username. Do this from console.

This specific problem can happen if you've been using "sudo" with X applications. Use "kdesudo" instead from within X.

If you use, for example, "sudo bash" then run an update or install, you will overwrite your home directory config files with new ones owned by root. KDE login as nonpriv user will fail to start because it cannot access the config files it needs.

Possible errors shown in /var/log/auth.log

mplayer no video in X

The selected video_out device may be incompatible with the codec. The xv (vo=xv) (mplayer -vo xv) is typically the default. You can specify the video output driver from the command line. For example:

mplayer -vo null vlccap01.avi               Produces audio and no video.  
mplayer -vo xv vlccap01.avi                 default video output.
sudo mplayer -vo fbdev2 vlccap01.avi        framebuffer driver requires privileged user.  full screen video.
                                            /dev/fb0 is the framebuffer device you can chmod it to grant permission.
                                            chmod a+rw /dev/fb0
                                            framebuffer typically used to putout to text console terminal

mplayer -vo gl2 -fs -zoom -xy 1280 vlccap01.avi
                                            full screen video using OpenGL for maximum performance

mplayer supports many output drivers: X11, Xv, DGA, OpenGL, SVGAlib, fbdev, AAlib, DirectFB, but you can use GGI, SDL (and this way all their drivers), VESA (on every VESA compatible card, even without X11).

Find your correct display driver and edit the mplayer configuration file to set it as the default.

vi ~/.mplayer/config

If you need to know the available list of options type this:

mplayer -vo help

Some example options to put into mplayer config file:

ao=alsa
vo=xv
stop-xscreensaver=yes
subfont-osd-scale=4.4