My laptop sometimes can't boot to X when it isn't on AC power

Question

I have a 2021 ROG Zephyrus G14 laptop with Ubuntu 22.04, which I usually run while plugged into the wall. When it's not plugged it and I try to boot it, the boot process sometimes doesn't make it all the way to the graphical login screen. Instead, just before the point where the graphical login screen would usually be displayed, I see a screenful of cryptic lines about "nouveau", like this:

Jul 31 08:42:17 Frost kernel: [   15.762402] nouveau 0000:01:00.0: mc: intr 00000040
Jul 31 08:42:17 Frost kernel: [   15.762542] nouveau 0000:01:00.0: mc: intr 00000040
Jul 31 08:42:17 Frost kernel: [   15.762679] nouveau 0000:01:00.0: mc: intr 00000040
Jul 31 08:42:17 Frost kernel: [   15.762817] nouveau 0000:01:00.0: mc: intr 00000040
Jul 31 08:42:17 Frost kernel: [   15.762955] nouveau 0000:01:00.0: mc: intr 00000040
Jul 31 08:42:17 Frost kernel: [   15.763087] nouveau 0000:01:00.0: mc: intr 00000040
Jul 31 08:42:17 Frost kernel: [   15.763230] nouveau 0000:01:00.0: mc: intr 00000040
Jul 31 08:42:17 Frost kernel: [   15.763367] nouveau 0000:01:00.0: mc: intr 00000040

I can switch to a TTY and log into zsh there, but after maybe 30 seconds that too gets filled with these messages and apparently stops responding to input. None of those lines seems to be left in /var/log/dmesg* afterwards when I boot up properly again.

How can I start debugging this? I have an RTX 3060.

Here are some example journalctl logs from an unsucessful boot (not plugged in) and a successful boot (plugged in): https://gist.github.com/Kodiologist/a7136bf44a814e113aa51c9ebe09292e

Answer 1

I think @ChanganAuto's comment did it:

[...] Now, regarding your issue: 1. Disable Secure Boot in UEFI 2. Install the recommended Nvidia drivers (Software & Updates > Additional Drivers), reboot.

I used ubuntu-drivers devices (from this answer) to identify the recommended version of the proprietary Nvidia driver for my system (namely nvidia-driver-515) and installed it (after disabling Secure Boot), and I can no longer reproduce the problem.