I too suffered from this issue after the xorg updates in question. My Toshiba Satellite M45-S265 laptop uses an Intel 915GM graphics card. I also stopped experiencing this issue when switching to GDM. I reverted back to the older xorg package versions as mentioned above, which got rid of the issue. I can now use KDM with no errors.
Prior to this, the only way I could still login with KDM was to hit "ESC" when the Kubuntu splash screen appeared, then hit CTRL+C repeatedly after the bootup steps started appearing onscreen.
I too suffered from this issue after the xorg updates in question. My Toshiba Satellite M45-S265 laptop uses an Intel 915GM graphics card. I also stopped experiencing this issue when switching to GDM. I reverted back to the older xorg package versions as mentioned above, which got rid of the issue. I can now use KDM with no errors.
Prior to this, the only way I could still login with KDM was to hit "ESC" when the Kubuntu splash screen appeared, then hit CTRL+C repeatedly after the bootup steps started appearing onscreen.