My goal here is to get boot printk’s to understand a hardware compat issue, so first I’m looking for info on how to setup a boottime serial console with qubes.
From what I saw:
- console= kernel parameters are ignored, and we see through dmesg that printk get directed to tty0 and hvc0
- some information exist on qubes website (Safe Remote Dom0 Terminals | Qubes OS), but they are only applicable to a running system, and won’t help getting early kernel logs
Then, as is not uncommon those days on a laptop, I do not have an RS232 interface. The kernel does support console=ttyUSB to cope with this, but how we can make it work in the qubes model, where we cannot even attach a USB/serial device do dom0, is not yet clear to me either.
Any hint to get those early printk’s to the outside world ?