Display port connection

User Support
1

Hello,
I am still new to Qubes OS and struggling a bit with my setup.
So far, I have connected my desktop computer to my display through HDMI using a PCIe 3.0 graphic card.
Now I like to use my display port connection with the display (HDMI does work).
Whenever I plug my connection into the display port, Qubes starts, but then ends up with a black screen
so I can not even pass the password step.
The display port connection is working with a different OS, so it´s not the problem of the display port or graphic card.
The resolution of my screen is: 3440x1440

I have read: Video RAM adjustment for high-resolution displays
“Caution: This page is intended for advanced users.” - which I am not…
GUI Configuration | Qubes OS,
but I am not sure, if this relates also to external PCIe graphic cards or not, but I tried…

value for the min RAM calculated: (3440x1440*4/1024)=19350, so lets say 22000…
so I typed into the terminal in dom0:

qvm-features dom0 gui-videoram-min 22000
restarted my comp

But no changes, still the display port connection does not work.

Can anyone please be so kind and give me a hint on what to do, so I can use the display port connection.

Thanks in advance!

2

I am having a similar issue with with my second DP connection. I’m pretty sure it’s a config issue somewhere. I tried setting my desktop to (3440 *2 monitors)x1440 and even tried setting the overhead to match. Second monitor will go into sleep mode for a few seconds, then come back on, but display nothing, then go back to sleep after 15-20 seconds. Then it will repeat. The whole time, my desktop is pretty useless while it tries to connect/disconnect the monitor. Doesn’t matter which port I start with, the second port does this. Didn’t do this with a pair of 27" monitors over display port. I even did a fresh install of Qubes.

Have you setup any monitor profiles in Settings->Display? I had had limited success with creating a profile and turning on the auto-apply feature. Granted, I have two monitors, not one.

3

Fixed this by manually setting monitor refresh rates to 60Hz each. 100hz and 144hz cause second monitor to lose it’s mind.

4

Well, I have given up trying to solve the problem.
I just use my HDMI port.
I tried:
In “DOM Display Setting” I can only check 50 or 30 Hz, I use 50 Hz.
I will update my graphic card driver next weekend, maybe this will solve the issue.
I only have one monitor.