serial console autodetection not working on powermac

[Benjamin Herrenschmidt]

On Sat, 2007-12-01 at 15:40 +0100, Olaf Hering wrote:
> How is the serial console autodetection supposed to work with current
> kernels? arch/powerpc/kernel/legacy_serial.c is not compiled unless
> CONFIG_PPC_UDBG_16550 is selected.
> Even if I force this config option, legacy_serial_console remains -1 and
> the ch-a/ch-b check in check_legacy_serial_console() does not trigger.
> Can the ch-a/ch-b check in check_legacy_serial_console() trigger anyway?
> 
> The autodetection used to work in earlier kernels.
> 
> A compiletime check for CONFIG_SERIAL_PMACZILOG_TTYS is also required,
> to switch between ttyS and ttyPZ. Currently ttyS is hardcoded.

It might well have bitrotted. It should be taken out of that file
anyway. I'll have a look next week. Remind me if I forget :-)

Ben.