One of my displays randomly turns black, sometimes staying black, sometimes turning back on after a few seconds, sometimes flickering between on and off. The backlight is still on, the OS does not seem to detect a missing display. Turning the display off completely and on again fixes the issue most of the time, however only for another few hours of usage. I'm trying to figure out if this is a hardware issue or a software issue.

The display in question is one of two identical Dell U2515H, each connected to a separate DisplayPort on a Gigabyte mainboard, running a current Fedora Linux. There's no discrete GPU installed, the system uses the Core i5's integrated GPU. One of the displays shows the symptoms described, the other one is fine. Here's what I have tried unsuccessfully so far:

  • swapped the DisplayPort cable for a new one
  • switched DisplayPorts on the computer (the mainboard has two DisplayPorts): Behavior stayed with the panel
  • switched primary and secondary screen in Fedora
  • switched from miniDisplayPort input to DisplayPort input (display has both connectors)

Any pointer is greatly appreciated!

Update: It was a faulty display, called Dell's customer support and got it replaced free of charge. Thank you all!

  • 2
    Faulty monitor given your testing ... – DavidPostill Dec 6 '17 at 15:14
  • sounds like it... how about trying it on another computer? – Digital Lightcraft Dec 6 '17 at 15:34

Sounds like a faulty or dying panel display driver within the display itself. That you move ports and change cables emphasise that.

Your computer is happy talking to the display (or it would not show up), happy transferring data (the display can go away and come back without apparently upsetting the computer) and it would seem to imply that the first "signal input" stage is fine.

Your backlight is on, so it is not a power supply issue. A PSU issue would also disconnect the monitor from Windows, so again it isn't that.

Your problem is that randomly the display simply "stops". Given all your other factors it quite firmly places the fault around the actual LCD panel driver. It could be anything from a dry joint, a slightly loose connector, a blown capacitor or some dying silicon.

It definitely doesn't sound like the problem is with your computer.

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