I just "fixed" this: turns out, I have, at some point in the past, added `blacklist amdgpu` to `/etc/modprobe.d`, as part of an unrelated troubleshooting session probably, and forgot about it.
I don't know why that wouldn't break 6.5.0-13 as well; maybe `update-initramfs` failed or wasn't executed so the config didn't get into the initramfs image.
Anyway, I removed the blacklist line and ran `update-initramfs`, after which everything works fine.
I just "fixed" this: turns out, I have, at some point in the past, added `blacklist amdgpu` to `/etc/modprobe.d`, as part of an unrelated troubleshooting session probably, and forgot about it.
I don't know why that wouldn't break 6.5.0-13 as well; maybe `update-initramfs` failed or wasn't executed so the config didn't get into the initramfs image.
Anyway, I removed the blacklist line and ran `update-initramfs`, after which everything works fine.
Sorry for the distraction.