I have been having a lot of problems with
xscreensaver and DPMS. A few months back DPMS stopped working and randomly xscreensaver would randomly not work as well. (Arch linux, xfce4, 4.8.7-1-ARCH)
As far as xscreensaver I tracked the issue to xfce4-power-manager it was sending some kind of commands to xscreensaver preventing it from running. (found a tip to this on an xscreensaver faq). Killed xfce4-power-manager and now xscreensaver activates properly.
Now I am back to my bigger issue of DPMS not working. Few things that i know I will be asked:
xset dpms force suspend/standby/offrun manually works perfect on all four of my monitors every time.
xset qreturns the following:
Standby: 0 Suspend: 300 Off: 2100 DPMS is Enabled Monitor is On
I have tried to set DPMS settings in various places (xset, xscreensaver-demo config, etc) to no avail.
xscreensaver does NOT keep asking for password as if input was being detected, this leads me to believe there is nothing coming in on /dev/input/event* - I did
evtest /dev/input/event0-16and didn't see anything popping up randomly that would cause this. I believe xscreensaver would be constantly showing the password pop up if input was the reason my monitors don't blank.
Being I have four monitors this is a real nightmare as I am constantly having to turn them all off and back on all the time and constantly leaving them on overnight by accident.
I will provide any info required.