Re: Problem with Nvidia 6800 driver
If you've not already done so, please read the NVIDIA driver README ( /usr/share/doc/NVIDIA_GLX-1.0/README.txt ), as there are several issues with your X configuration that are documented in the README. For example, the X dri module should not be used with the nvidia driver.
Also, I'd strongly suggest using the much more recent 1.0-7676 driver, as the 1.0-7174 that you're using is only meant for legacy videocards (and your GeForce 6800 is most definitely not a legacy card).
Your xorg.conf contains only one screen section which is specifying a 1440x900 resolution. Unless both your laptop and your plasma display have the same native resolution and modeline, its highly unlikely that your current configuration will work properly across both of them. Therefore, you'll need to specify an explicit modeline for at least one of your display devices, and potentially an additional screen section that uses the modeline. If you need help with this, please start X with the following command:
startx -- -logverbose 5
and then generate and post an updated bug report.
Which screen is going blank when you try to switch away from the plasma, the plasma or the laptop?