[CentOS] Upgrade to 8.4 .2105 Problems

Sat Jun 5 03:30:27 UTC 2021
Alan McRae <amcrae at island42.net>

The yum upgrade from 8.3 to 8.4 on my main machine  looked as if it was 
working fine so I went to have a coffee.

When I came back the screens were blank so I don't know what happened. 
On rebooting the screens are still blank.

I have two graphics cards running three displays.

I have a "rescue" system on the same machine that upgraded from 8.3 to 
8.4 fine. The 3 screens work fine on this.

I am not sure the upgrade completed properly. For example the new kernel:


was not present in /boot. Even worse, "yum upgrade" said there was 
nothing to do and would not install it. I installed the kernel package 
manually.  /etc/redhat-release says CentOS Linux release 8.4.2105

My main question is: Where are the config files for the screen(s). This 
used to be something like /etc/X11/xorg.conf.

Since I have a working rescue system my current plan is to compare/copy 
the config files.

Suggestions please as to where I should start. It is difficult to work 
without a GUI. I have ssh access to the machine.




Alan McRae