Created attachment 102152 [details]
debug output from 3.6.3

Don't know if this will help any, but 3.6.3 was the last kernel in which I was
able to a) run nouveau successfully and b) have the full monitor-off timeout
stuff work.

I don't pretend that I tried every in-between version, but in general between
3.7 and 3.11 I was never able to find the right magic words to get any kind of
operational display, or perhaps things were broken.  3.11 onwards works but
then we have the DP DPMS issue which is the original point of this bug report.