what happens if you don't use X -configure? that option is rarely necessary any more and has become known problematic more than helpful lately. if any configuration is necesary (such as device options), then just a tiny snippet is enough. eg:
---
Section "Device"
Identifier "Card0"
Driver "nouveau"
#Option "AccelMethod" "none"
EndSection
---
another thing is to try forcing modesetting driver.
.mrg.
