0

I'm using Linux Mint 21.1 on a Lenovo ThinkPad P50. I've plugged in two identical external monitors (Asus PB287 - 4k) via a Lenovo Docking Station.

The first monitor is using Displayport (should support 60Hz), the second Monitor only via HDMI (there is no second DP slot). It should only support 30Hz that way.

During booting, all three monitors (Laptop + 2 external) are working. When entering the disk-encryption password, I see it everywhere. The same on the login-screen: All three monitors are working. The password prompt is only one one monitor (the HDMI-one).

After login however, the HDMI-monitor turns black. I can see all three monitors in the display settings, but I can't enable the third one (HDMI). When I click the enable-toggle-bar and press "Apply", all monitors turn black for a fraction of a second (which is normal), and turn back on the way they where before. The third monitor is immediately disabled again and nothing changed.

dmesg does not produce any messages during that process.

I'm using the nVidia driver (v525.85.05).

Display settings

I previously used Windows 10 with the exact same hardware setup, and everything worked without issues. This, and the fact that all three monitors are working during booting, show me that the Hardware-side supports this. It should therefore be a software issue.

I have the feeling that this is because the two external displays are the same type. The nVidia settings dialog shows a GUID for one monitor, but not the other (maybe because it's disabled?). Interestingly, it also shows "Signal: Displayport" and "DisplayPort Connection Type: DisplayPort" for both external monitors, although one is connected via HDMI.

Improve this question

2 Answers 2

Reset to default
0

I just ran into this problem also. To fix it, I clicked on the Reset to Defaults button, and the second external monitor came back on.

Improve this answer
1
  • Thanks for your answer, unfortunately it didn't work for me. I switched to the xfce desktop instead. While it is buggy as well, at least I can use 3 monitors (albeit only at 30Hz, and with some other very annoying, but less severe issues).
    – maja
    Commented Jan 9 at 10:25
0

I just ran into the same exact problem using Mint. No idea where the Reset To Defaults option is but I unplugged the monitor while the computer was still on and then plugged it back in. Texas way of "Reset To Defaults".. Now it works.

Improve this answer
New contributor
Interactive Sci Fi Today is a new contributor to this site. Take care in asking for clarification, commenting, and answering. Check out our Code of Conduct.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .