With no console= given the kernel will use the graphical console and if
we give one console= then that will be used instead. But sometimes we
want both a serial console and a graphical one to work. This would be
consistent with the EFI menu and sd-boot showing on both already. It
also makes the impact of a wrongly detected-but-missing VirtIO console
lower when we emit it alongside of the other consoles we detect.
Collect all detected consoles and emit them via console= with the same
priority we used before to select them. This means for the main console
there is no change but we get additional ones enabled. This helps with
boot output and having a login presented, yet the main console is still
special and gets the emergency output at boot (we should somehow surface
that on the additional consoles but that's another topic). If we only
see the graphical console (or none), we don't need to emit anything a
the kernel already selects it itself. This also avoids suppressing the
non-x86 kernel serial console detection. As mentioned above, the VirtIO
console being wrongly added is now also less impactful. But for non-x86
ACPI case we could detect the serial so that console=hvc0 won't stop the
kernel serial auto-detection.
Kai Lüke
924552cfba