SDDM Problem (?) With Multiple Screens

[Richard Heck]

On Fedora 22 with KDE and SDDM.

I have for some time been using two monitors with a GeForce 610 video
card. After an update a while ago, the DVI output just stopped working
at boot time, at least when the HDMI output was also being used. I was
able to use VGA with HDMI, but now another update has messed that up.
So, e.g., the machine boots, but I never see the login screen, because
the monitor it's meant to be on isn't showing anything. Oddly enough,
though, the monitor does wake up. But it's just black.

This is with sddm.

If I go to a virtual terminal and log in there, then run startx,
everything comes up just fine. The only problem there is that the wrong
monitor is now the default. So there's nothing wrong with the hardware.

I am thinking that maybe the X settings, or sddm settings, have been
corrupted somehow, so I'm wondering which files I might need to delete
to force all this to be reset.

If it matter, I am using the rpmfusion nvidia drivers.

Thanks for any help,
Richard Heck