I have now determined that it seems specific to my turning off the monitor. If I leave it on even overnight, X keeps working as expected. The problem is that the monitor is not turned off - so the backlight is going on a black screen all the time. James Pulver CLASSE Computer Group Cornell University On 09/12/2016 09:27 AM, James M. Pulver wrote: > Cross posted from serverfault: > > I'm having the weirdest issue. We use SL7.2 and have a network home > directory and AD + SSSD for auth. This means I can go to different > computers and get a consistent home dir as well as UID/GID etc. I have a > physical KVM to set up computers more easily. > > I started having an issue where my workstation would stop displaying X > to my monitor. The monitor will say "No Signal" It would work fine until > I switched away via the KVM to another computer, when I switched back X > would not display. I could connect via Bomgar and see my X session, it > was fine. I could ctrl-alt-F3 and the virtual terminal would display, > but the only way to get X back was to reboot. > > I thought it might be the KVM, so I connected the monitor via DVI > directly to the workstation. No change. > > I thought it was an issue with the hardware or the OS install, so I set > up a brand new Lenovo P510 with a new SL7.2 install. Now it will loose X > if I just don't use it for a while (I think it's the screen locking?). > > I thought it might be the monitor - maybe it's old and loosing signal, > or the new Display port to DVI adapter can be funky, so I installed a > brand new BENQ GW2765, connected directly via Display Port to the nVidia > card (this card only has Display Port connectors - 4x). No change. > > However, this last time Bomgar could not show the X session... > > So now I'm thinking - it HAS to be software, and it has to be something > in my configuration. But I don't really even know where to start looking > - /var/log/messages and /var/log/Xorg.0.log don't show anything that's > obvious to me. > > How can I fix X not coming back? >