External DELL screen is not working with Ubuntu 21.04 on Thinkpad

gb flag

I am trying to connect my Lenovo, Thinkpad laptop with my DELL external screen via HDMI. Either the external screen blinks and shows the colors in very bad quality or it doesn't connect all with "No HDMI signal from your device" message. Laptop runs Ubuntu 21.04.

My external screen works fine via the same HDMI cable with another laptop. Moreover, my Levono, Thinkpad also works fine with another external screen via HDMI.

I have tried so many proposals found in the forums here but nothing helped. Some of the things I tried was disabling secure boot, editing /lib/systemd/system/gdm3.service, restarting gdm3, installing nvidia-driver-435, checking about blacklist-nvidia.conf files, running update-initramfs -u etc etc but nothing worked.

Do you maybe have any idea what is happening? Thanks in advance!

~ $ xrandr

Screen 0: minimum 16 x 16, current 1920 x 1080, maximum 32767 x 32767
XWAYLAND0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 310mm x 170mm
   1920x1080     59.96*+
   1440x1080     59.99  
   1400x1050     59.98  
   1280x1024     59.89  
   1280x960      59.94  
   1152x864      59.96  
   1024x768      59.92  
   800x600       59.86  
   640x480       59.38  
   320x240       59.52  
   1680x1050     59.95  
   1440x900      60.03  
   1280x800      59.99  
   720x480       59.71  
   640x400       59.95  
   320x200       58.96  
   1600x900      59.95  
   1368x768      59.88  
   1280x720      59.86  
   1024x576      59.90  
   864x486       59.92  
   720x400       59.55  
   640x350       59.77  

~ $ sudo lshw -C display

       description: VGA compatible controller
       product: UHD Graphics 620
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       logical name: /dev/fb0
       version: 07
       width: 64 bits
       clock: 33MHz
       capabilities: pciexpress msi pm vga_controller bus_master cap_list rom fb
       configuration: depth=32 driver=i915 latency=0 mode=1920x1080 visual=truecolor xres=1920 yres=1080
       resources: iomemory:2f0-2ef iomemory:2f0-2ef irq:158 memory:2ffa000000-2ffaffffff memory:2fa0000000-2fafffffff ioport:e000(size=64) memory:c0000-dffff
ChanganAuto avatar
us flag
Honestly, at this point the best suggestion is to test it in a live session (use 21.10 instead because 21.04 has only a few months of support left) and if it works install a fresh 21.10. What you've been doing so far couldn't possibly fix it and only make things worse. Namely, installing old and deprecated Nvidia drivers for an Intel Graphics and messing with gdm. Just don't! When you don't know what you're doing ask first!
gou avatar
gb flag
I was trying everything in Ubuntu 20. Then, I upgraded to 21.04 for the reason you proposed. So I have a fresh system and still it doesnt work. Drivers seemed messed anyway since external screen never worked and maybe someone would argue that you first try and then ask ;)
ChanganAuto avatar
us flag
Yes, you should try first IF you know what you're doing which isn't the case here. Again, how does it behave in a live session?
gou avatar
gb flag
Good point :) I tried Ubuntu 21.10 live session but I still have the same problem. The external screen blinks, shows the colors with very bad quality and then I get "No HDMI signal from your device" message.

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.