Re: (beta) nvidia-settings not detecting VGA monitor correctly
I followed your suggestions and did a little more poking around as well. I got rid of twinview, re-generated the Modeline for 60Hz, and changed 1280x1024_75 to my1280x1024. I know the modes are within spec because they've worked before and if it tried sending a signal out of spec the LCD displaced the message "unsupported input" or something to that effect. Instead of just says "no input"
It seems that specifying a ModeLine doesn't exempt it from EDID validation. Additionally, the line Option "ModeValidation" "NoEdidModes" seems to mean only that it will not include modes auto-generated from EDID, but it still tries to validate manually defined modes with the EDID data.
So then I went back to using the Option "UseEDID" "false" line with my twinview setup, which worked fine for the CRT but I don't know how to define a Modeline for the second monitor (the DFP) and since it couldn't generate them using EDIDs it had no modes and wasn't initialized.
See the two attached nvidia-bug-reports.