DisplayPort monitor not detected if switched off and on again

Solution 1:

I just had the same problem with a Dell u2913wm connected to a i5-5775c Iris Pro 6200 via Displayport. When I switched inputs on the monitor, it would not display an image afterwards.

The problem could be solved by using ssh to log into the machine and running:

env DISPLAY=:0 xset dpms force off
env DISPLAY=:0 xset dpms force on

While not very practical, that would turn the screen back on.

After reading the answer that mentioned turning off DDC/CI, I fiddled with my monitor settings since manually setting dpms off and on is too cumbersome. DDC/CI setting did nothing for me, but my monitor had an additional Displayport 1.2 setting that was disabled.

After switching the Displayport 1.2 setting to enabled, my monitor started working again after changing inputs, or turning it off, just as it is supposed to.

Solution 2:

I have this same issue. However, my screen also wont sleep. So any workaround (eg. turning screen on/off) hits this issue.

This bug has been raised on LaunchPad:

launchpad >> bug 1313539

However, it is currently marked as a duplicate of a more generic bug:

launchpad >> bug 1308105 (still open)

UPDATE: Jan-17

I just tried with a DVI Dual-Link cable.

Unfortunately my video card does not support Dual-Link, only Single-Link. However, to the best of my knowledge the HP DL139A ('DMS-59 to DVI Dual-head Y-Cable') does. (Anyone else know?)

No issues (screen saver, screen sleep, or wakeup) under DVI, except drops to 1920x1200 resolution. Inconclusive, but issue is NOT present with same 27" screen, and identical OS / driver setup.

UPDATE: Jan-19

New (bigger/faster) video card still on order.

Tried with another video card, with dual DisplayPort (instead of DMS-59).

Unfortunately the HP adapter (HP P/N 481409-220, included) is only DisplayPort to DVI Single-Link. They have another adapter (HP P/N NR078AA) that does DisplayPort to DVI Dual-Link, but it costs USD $150 (a rip off).

No issues (screen saver/screen sleep, or wakeup) under DVI, except drops to 1920x1200 resolution. Direct DisplayPort cable (from this card) still has same issues.

UPDATE: Feb-12

Resolved for now, by moving screen close to PC and using (Samsung supplied) DVI Dual-Link cable that came with monitor.

Still unable to use properly with DisplayPort cable.

Solution 3:

I had the same issues. I connect my Windows 7 PC to my Dell 2709W monitor by DisplayPort. (Nvidia GTX 750)

I found solutions here: https://superuser.com/questions/630555/

I disabled the "DDC/CI" in my monitor setting. This solved the problem. I hope this helps.