I have recently acquired a Dell XPS 9500 laptop with a Core i9 10th gen and nvidia 1650Ti.
I have been able to successfully install Ubuntu 20.04. However, I am unable to connect two monitors at the same time! Whenever I plugin a monitor, one stops working and the other works! Both monitors use USB-C. I tested with 2 different monitor models; the LG Ultrafine 5k and Lenovo Thinkvision, same behavior.
I have tested with Nvidia driver and nouveau, still the issue persists.
My kernel version is 5.11.0-27-generic
Here is the xrandr output when one external screen is connected:
Screen 0: minimum 8 x 8, current 8960 x 2880, maximum 32767 x 32767
eDP-1-1 connected 3840x2400+0+0 (normal left inverted right x axis y axis) 336mm x 210mm
3840x2400 59.99*+ 48.00
3840x2160 60.00 60.01 59.98 59.97
3200x1800 59.96 59.94
2880x1620 59.96 59.97
2560x1600 59.99 59.97
2560x1440 59.99 59.99 59.96 59.95
2048x1536 60.00
1920x1440 60.00
1856x1392 60.01
1792x1344 60.01
2048x1152 59.99 59.98 59.90 59.91
1920x1200 59.88 59.95
1920x1080 60.01 59.97 59.96 59.93
1600x1200 60.00
1680x1050 59.95 59.88
1600x1024 60.17
1400x1050 59.98
1600x900 59.99 59.94 59.95 59.82
1280x1024 60.02
1440x900 59.89
1400x900 59.96 59.88
1280x960 60.00
1440x810 60.00 59.97
1368x768 59.88 59.85
1360x768 59.80 59.96
1280x800 59.99 59.97 59.81 59.91
1152x864 60.00
1280x720 60.00 59.99 59.86 59.74
1024x768 60.04 60.00
960x720 60.00
928x696 60.05
896x672 60.01
1024x576 59.95 59.96 59.90 59.82
960x600 59.93 60.00
960x540 59.96 59.99 59.63 59.82
800x600 60.00 60.32 56.25
840x525 60.01 59.88
864x486 59.92 59.57
800x512 60.17
700x525 59.98
800x450 59.95 59.82
640x512 60.02
720x450 59.89
700x450 59.96 59.88
640x480 60.00 59.94
720x405 59.51 58.99
684x384 59.88 59.85
680x384 59.80 59.96
640x400 59.88 59.98
576x432 60.06
640x360 59.86 59.83 59.84 59.32
512x384 60.00
512x288 60.00 59.92
480x270 59.63 59.82
400x300 60.32 56.34
432x243 59.92 59.57
320x240 60.05
360x202 59.51 59.13
320x180 59.84 59.32
DP-1-1 connected primary 2560x2880+3840+0 (normal left inverted right x axis y axis) 600mm x 340mm
3840x2160 60.00 +
2560x2880 60.00*
3200x1800 60.00
2560x1440 60.00
640x480 59.94
DP-1-2 connected 2560x2880+6400+0 (normal left inverted right x axis y axis) 600mm x 340mm
2560x2880 60.00*
DP-1-3 disconnected (normal left inverted right x axis y axis)
DP-1-1-8 disconnected (normal left inverted right x axis y axis)
DP-1-1-1 disconnected (normal left inverted right x axis y axis)
And here it is with 2 screens connected (both LG Ultrafine 5K in this case):
Screen 0: minimum 8 x 8, current 8960 x 2880, maximum 32767 x 32767
eDP-1-1 connected primary 3840x2400+0+0 (normal left inverted right x axis y axis) 336mm x 210mm
3840x2400 59.99*+ 48.00
3840x2160 60.00 60.01 59.98 59.97
3200x1800 59.96 59.94
2880x1620 59.96 59.97
2560x1600 59.99 59.97
2560x1440 59.99 59.99 59.96 59.95
2048x1536 60.00
1920x1440 60.00
1856x1392 60.01
1792x1344 60.01
2048x1152 59.99 59.98 59.90 59.91
1920x1200 59.88 59.95
1920x1080 60.01 59.97 59.96 59.93
1600x1200 60.00
1680x1050 59.95 59.88
1600x1024 60.17
1400x1050 59.98
1600x900 59.99 59.94 59.95 59.82
1280x1024 60.02
1440x900 59.89
1400x900 59.96 59.88
1280x960 60.00
1440x810 60.00 59.97
1368x768 59.88 59.85
1360x768 59.80 59.96
1280x800 59.99 59.97 59.81 59.91
1152x864 60.00
1280x720 60.00 59.99 59.86 59.74
1024x768 60.04 60.00
960x720 60.00
928x696 60.05
896x672 60.01
1024x576 59.95 59.96 59.90 59.82
960x600 59.93 60.00
960x540 59.96 59.99 59.63 59.82
800x600 60.00 60.32 56.25
840x525 60.01 59.88
864x486 59.92 59.57
800x512 60.17
700x525 59.98
800x450 59.95 59.82
640x512 60.02
720x450 59.89
700x450 59.96 59.88
640x480 60.00 59.94
720x405 59.51 58.99
684x384 59.88 59.85
680x384 59.80 59.96
640x400 59.88 59.98
576x432 60.06
640x360 59.86 59.83 59.84 59.32
512x384 60.00
512x288 60.00 59.92
480x270 59.63 59.82
400x300 60.32 56.34
432x243 59.92 59.57
320x240 60.05
360x202 59.51 59.13
320x180 59.84 59.32
DP-1-1 connected 2560x2880+3840+0 (normal left inverted right x axis y axis) 600mm x 340mm
3840x2160 60.00 +
2560x2880 60.00*
3200x1800 60.00
2560x1440 60.00
640x480 59.94
DP-1-2 connected 2560x2880+6400+0 (normal left inverted right x axis y axis) 600mm x 340mm
2560x2880 60.00*
DP-1-3 disconnected (normal left inverted right x axis y axis)
DP-1-1-8 disconnected (normal left inverted right x axis y axis)
DP-1-1-1 disconnected (normal left inverted right x axis y axis)
It seems it's detecting that something is connected whether it is really connected or not, and with a wrong resolution, and the monitor stays blank anyway.
