i'm using intel haswell chip for my gpu. i can wake out of the screensaver and the lock screen shows nicely. when i wake after the monitor has been powered off, i get either blank or garbled or offset screen. i'm using gnome-screensaver. i can still type my password and enter, and it will come back properly. it just doesn't display the lock screen. sometimes when i wake it, it looks like it is usable. the mouse moves, but nothing responds. i type my password and it works.
i've tried xscreensaver and it's worse. i have to power down to get out of it (there may be another way, i just don't know it).
currently i'm trying some different settings in system->brightness and lock. any ideas?