Re: [Qemu-devel] [PATCH] debugcon: support for debugging consoles (e.g. Bochs port 0xe9)

[François Revol]

> Makes sense.  Either way, it works with my patch looking something
> like:
>
>       -chardev stdio,id=seabios \
>       -device isa-debugcon,iobase=0x402,chardev=seabios
>
> ... should do the job.

Btw,
I once added another method of debug output to ZETA, that was using the
low-level protocol used by laplink (nibble mode). I needed this for a
laptop that didn't have a serial port but still had a // one. This
allowed bidirectionnal debugging (including sending kernel debugger
commands) with a null-printer cable.
I also wrote code to support it in Haiku, though I'm not sure I've
added the receiving driver yet.
See:
http://dev.haiku-os.org/browser/haiku/trunk/src/add-ons/kernel/debugger/laplinkll

I don't know if the parallel port emulation in QEMU supports dumping
bytes at nibble mode yet, it might be interesting to add this anyway.
Though it should also be possible to just use 8bit mode and dump data
straight to it as with the 0x402 port.

François.