GUI login yields blank screen after password supplied

[novice-linux-user]

Hi.

WARNING: I am a total newbie to Linux. I don't know much in terms of Linux internals or terminology, so if you ask me something, you may have to explain how to get the answer, too. Sorry (and thanks!)!

A little info re: system particulars to start...

OS = CentOS 8 (4.18.0-147.8.1.el8_1.x86_64)
Graphics adapter = Nvidia Quadro P620 (installed driver: NVIDIA-Linux-x86_64-440.82)
Lenovo ThinkPad P73 laptop

Problem symptoms:

When I boot after "systemctl set-default graphical.target", I do see the GUI login. However...
After I enter my password and select the GUI I want to use (no matter which one I choose), I get a totally blank screen - hung?
If I connect via ssh and "systemctl restart display-manager", I can successfully login via the GUI.
All subsequent reboots result in the same problem (assuming I do not "systemctl set-default multi-user.target" in the interim).

If I "systemctl set-default multi-user.target" and reboot, I can successfully "startx" and, upon answering a keyring password prompt, I am successfully logged in, as well (but not offered a GUI selection in the process).

This problem arose sometime after I upgraded the nvidia driver.

The following messages are logged in file "Xorg.n.log{.old}" when booting after "systemctl set-default graphical.target"...

[ 21.942] (II) NVIDIA(0): Detected PCI Express Link width: 16X
[ 21.942] (EE) NVIDIA(GPU-0): Failed to acquire modesetting permission.
[ 21.942] (EE) NVIDIA(0): Failing initialization of X screen
[ 21.943] (II) UnloadModule: "nvidia"
[ 21.943] (II) UnloadSubModule: "glxserver_nvidia"
[ 21.943] (II) Unloading glxserver_nvidia
[ 21.943] (II) UnloadSubModule: "wfb"
[ 21.943] (II) UnloadSubModule: "fb"
[ 21.943] (EE) Screen(s) found, but none have a usable configuration.
[ 21.943] (EE)
Fatal server error:
[ 21.943] (EE) no screens found(EE)

In my opinion (not worth much, of course), this seems to be an issue related to the order (init level?) in which GDM and/or "X" processes/services start. I say this because, when the login hangs (after a reboot following "systemctl set-default graphical.target") - init level 5? - and I "systemctl restart display-manager", everything seems to work after that. Also, when I reboot after "systemctl set-default multi-user.target" (init level 3?) and, then, "startx", it also works fine (no choice of which GUI to use, of course).

This is my very first post anywhere in any forum so please feel free to provide guidance, complain, etc.

[gerry666uk]

I don't know about the specific issue that you are having, but I have seen something similar:
When you install CentOS 8, there are a number of options (roles) you can select related to the GUI.
The "easy" way, is to make sure you choose one of the GUI options at install time, then you will get the logon screen automatically after boot up. You can then log in (e.g. using Gnome Classic) and get to the desktop. You don't need to issue any commands to do this.

BUT, if you installed it without one of the GUI options (as I did during testing) and then try to start the GUI manually, it might cause a blank screen (as happened to me). I needed it to work, so I just decided to use one of the GUI options at install time...

[TrevorH]

What is the output from cat /proc/cmdline ?