gvpio extender

[Ken T. <ke...@we...>]

Hello,

The parallel part of the IO-Extender *almost* almost works but I'm stuck. 

Tried two approches, one based on parport_amiga with hints of
parport_mfc3, the other is much the same with some parport_pc bits, the
justification for this being that the Ti data sheet says the parallel port
is standard 8255 PC hardware compatible.

They both behave the same way. I can insmod lp, parport and parport_gvpio,
see all the right things in /proc/iomen, /proc/interrupts, /proc/devices
and /proc/sys/dev/parport/.  Some printk's suggest interrupts are working
when I turn the printer off and on, and status bits look reasonable.

But if I try to lpr a file or cat a file directly into /dev/lp linux hangs
or blocks, heartbeat still running, cursor flashing but can't type or
switch consoles.  Magic sysreq won't sync or unmount but will reboot and
put task, register and backtrace info into dmesg.

The magic sysreq dmesg is the only debug info available and suggests it is
having a problem in chardev_open.

Where do I look ?

Ken.