DisplayPort Monitors No Longer Detected

Solution 1:

I had a slightly different issue, but hopefully some of this applies.

I had a brand new Debian 10.4 install on a Dell laptop (Latitude 5590), and was having issues getting external display ports working with the Dell D6000 dock.

The solution for me has been to:

1. Ensure secure boot is turned off in the BIOS (I also enabled legacy support - not sure if this is required)
2. Install the displaylink driver for ubuntu (5.3.1)
3. Create a file to persist xorg configuration (source):

/etc/X11/Xsession.d/45custom_xrandr-settings containing (source):

xrandr --setprovideroutputsource 1 0
xrandr --setprovideroutputsource 2 0
xrandr --setprovideroutputsource 3 0
xrandr --setprovideroutputsource 4 0
xrandr --output DVI-I-3-2 --mode 1920x1080
xrandr --output DVI-I-2-1 --mode 1920x1080

(You made need to run xrandr -q to check what your outputs are)

4. Modify /etc/pulse/default.pa (source) to avoid my Dock being suspended (screens turn off seemingly randomly), placing a comment # before load-module module-suspend-on-idle, then restart my laptop

I know to avoid Dell docks in the future.