Comment # 7 on bug 1200516 from Carlos Robinson

The machine has been working with no issues for months. Only recently, maybe a
week or two ago, it starting locking maybe three days after booting, or the
first day. Random.

With the 15.4 kernel it locks on the login prompt of sddm, after typing the
password and hitting enter. I can ssh, but keyboard is dead, and mouse moves
but doesn't respond.

I just did:

journalctl --boot=-1 > /tmp/mesg.txt

to capture the log of that boot. I will attach it now. I do see entries related
to nouveau.

I don't know when I will be able to try with the backport kernel you mention,
the machine is busy and so am I. When time permits :-)