I’m running Manjaro XFCE on my Dell Inspiron 3582 (Intel Pentium Silver N5000, Intel UHD Graphics 605) laptop, and HDMI doesn’t work when I’m running 5.10 kernel. When I was running Debian with 5.10 kernel it was working perfectly, however. Now I’m running 5.4 kernel on Manjaro and everything (including HDMI) is working just fine.
What happens is when I connect HDMI to my laptop, the screen on both laptop and external monitor is black (it’s working), and my laptop becomes unresponsive, so clicking on power button is the only way to restart it.
Did you try other (newer) kernels?
Does disconnecting HDMI cable bring back the laptop display?
Is the machine really unresponsive or just not showing any output, e.g. does it react to ping and/or can you ssh into it from another machine?
Actually, I didn’t as I was thinking that running LTS kernels is the best option for my laptop. Perhaps, I’m wrong but trying to run Fedora XFCE with its “everything should be a release version” was a terrible experience for me.
I was trying to restart it by typing a command but it didn’t work when I know for sure that it will work normally, hence the keyboard must be unresponsive. As for trying to ‘ssh into it from another machine’, I didn’t try that. Even if that works the best case scenario is still to restart a laptop and that’s it.
I’ll try to do that next time in a situation like this, thank you!