I had to add "UseDisplayDevice" "DFP" to the main device section as X always failed with a blank laptop screen. I am of course using the other Device section for the TV-Out that is currently failing, but don't know if this addition could have affected things.
After reading the link you gave to Bug #89290 I thought I would mention the following:
I have two devices section in xorg.conf:
Section "Device"
Identifier "nVidia Corporation NV17 [GeForce4 420 Go 32M]"
Driver "nvidia"
Option "UseDisplayDevice" "DFP"
EndSection
Section "Device"
Identifier "GeForce4 420 Go 32M TVOut"
Driver "nvidia"
Option "TVOutFormat" "SVIDEO"
Option "TVStandard" "PAL-I"
Option "ConnectedMonitor" "TV"
EndSection
I had to add "UseDisplayDevice" "DFP" to the main device section as X always failed with a blank laptop screen. I am of course using the other Device section for the TV-Out that is currently failing, but don't know if this addition could have affected things.