Downgrading Arch Linux Kernel

Published 2022-03-27 | Go Back

Yesterday, I had to match the kernel and the display driver versions when downgrading the Arch Linux kernel. Now I’m jotting it down as a memo.

I did a system upgrade yesterday on my Arch Linux install. The kernel was updated to version 5.16.16. After rebooting the machine, I noticed that the WiFi connection kept dropping and reconnecting, and it was very hard for me to open any website. I looked it up on my phone and found that there was this bug in recent kernel changes. Versions 5.16.14 and below seem unaffected.

After downgrading the linux package to 5.16.14, I couldn’t see the graphical login screen. This is not a surprise for me. I’ve seen this during my previous kernel upgrading, and reinstalling the nVidia display driver worked. I did that, but this time it didn’t work. Now I’m a bit surprised. I vaguely remember that the kernel version and the display driver version need to be “compatible”, although the exact reason has always been a puzzle for me. Let me downgrade nvidia-* packages to an arbitrary previous version. Uh, no luck.

I tried looking at various logs, but I couldn’t find a proper workaround. Now it’s time to roll back to the exact versions before the system upgrade. I looked at the pacman log at /var/log/pacman.log, and wrote down the versions for packages linux, nvidia, nvidia-utils, and nvidia-settings. Then I used downgrade to install those exact versions. It’s nice that downgrade can use local cached packages, and it also shows which versions were installed previously. This time it finally worked.

As a side note, I think the DKMS version of the nVidia display driver may not have this “compatible version” issue. That said, I switched away from it a long time ago, and I forgot why.