The problem started out of the blue (possibly after an update/upgrade) a few days ago, and I have been struggling with it ever since.
Every once in a while the screen goes blank and shows “no signal” message. There are only two ways to wake the monitor up: (1) shutdown and restart; (2) unplugging and replugging (which I may need to do more than once, at times). Unplugging and replugging occasionally results in a display change, with fonts getting much bigger.
When the screen goes blank, the computer is still running – e.g., the music, if it is played, keeps playing, etc. If it happens as I am typing and I continue the typing with the screen-gone-blank, what I have typed has indeed got typed.
This problem will recur after 1 minute, 10 minutes, half an hour, etc. – it appears completely random. There is no discernible activity that triggers it.
I am using Ubuntu 20.04.02.
The Gnome version is 3.36.8.
The graphics card is an integrated Intel:
Intel® Core™ i3-6100 CPU @ 3.70GHz × 4
Mesa Intel® HD Graphics 530 (SKL GT2)
The motherboard is ASRock H110M-HDV.
The port is VGA.
The monitor is a truly ancient ASUS.
The driver info is as follows:
$ lspci -k | grep -EA3 'VGA|3D|Display'
00:02.0 VGA compatible controller: Intel Corporation HD Graphics 530 (rev 06)
Subsystem: ASRock Incorporation HD Graphics 530
Kernel driver in use: i915
Kernel modules: i915
I have tried replacing the cable, and it changed nothing. I have also checked the temperatures, and there seems to be no overheating. The software is up to date.
All help much appreciated.