Late initialization of ttyPZ0 prevents console=ttyPZ0 from working (under qemu-system-ppc64)

[Richard W.M. Jones]

On Thu, Jun 07, 2012 at 10:20:44AM +0100, Richard W.M. Jones wrote:
> 
> I'm trying to get the qemu-system-ppc64 serial console working with
> our Fedora kernel.
> 
> I first tried various console={ttyS0,hvc0,ttyPZ0,etc} options, and
> none of them work.
> 
> However, *after* the machine has fully booted up, I can send messages
> to the qemu serial console by eg:
> 
>   cat /proc/cpuinfo > /dev/ttyPZ0
> 
> (none of the other serial-like devices work, just that one).
> 
> But the question is why the Fedora kernel can't send boot messages
> there.  I'm guessing it's because /dev/ttyPZ0 is initialized very late
> in the boot process?  (see attached 'dmesg' output)  Is there a way to
> get it to send console messages to any serial console, or to force the
> ESCC serial device to be initialized earlier?

I found the CONFIG_SERIAL_PMACZILOG_CONSOLE=y option.  I will try a
kernel that has this enabled and see if that works.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming blog: http://rwmj.wordpress.com
Fedora now supports 80 OCaml packages (the OPEN alternative to F#)
http://cocan.org/getting_started_with_ocaml_on_red_hat_and_fedora