I attach my Gigabyte P34Wv4-BW1T laptop to a 2nd monitor via HDMI. This monitor blacks out randomly. I think it's random, at least. I'm not sure if it's going into sleep mode or not. I went into my laptop and monitor settings and turned off any power saving and sleep modes. I tried the nouveau driver, nvidia "proprietary,tested driver" and the nvidia "proprietary" driver and I still have the same problem. I checked my cables and they are not loose.
I'm not sure what type of log would help diagnose the problem. I did do a dmesg -T and couldn't find something in the log that corresponded to the time that this happens.
Maybe the "ACPI Warning" is a culprit? The same problem happened again and I didn't see the ACPI Warning in the dmesg log, though.
Another thing is that when I am playing music through the hdmi cable (the monitor has speakers) and the screen blacks out, the audio shuts off as well. So that's why I thought it was the cable, but the cable is on their tight.
I tried a disabling the nvidia card and using the intel card. That did not help. I also tried connecting via different hdmi ports. Still does not work. Can anybody out there help?
Edit: i removed the nvidia drivers and disabled the nvidia card on my laptop. im just using the intel graphics. still having a problem. any ideas?
Edit: turned off power management (I think) and dpms:
$ xset -q
DPMS (Energy Star): Standby: 0 Suspend: 0 Off: 0 DPMS is Disabled
Edit: I don't see anything when I tail .xsession-errors
Edit: I installed Windows 10 and tried it all out. No problems with blacking out. It's not the cable or the hdmi port. Not a hardware problem! I really need some help.
Edit: It doesn't seem to be happening at a lower resolution of 2560x1080:
HDMI1 connected 2560x1080+1920+0 800mm x 335mm
3440x1440 50.0 + 30.0