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Re: Testing the functionality of a parallel port...

Michael Kahle said:

> I have greped for things that I thought would be relevant in /var/log and
> could not find anything out of the ordinary.  Any ideas?

by default linux doesn't put the parallel port in interrupt mode, most
parallel ports default to using IRQ 7. On my systems I force enable
the parallel port so it uses the IRQ instead of "polling" mode, this has
dramatically improved performance.

it may be that the kernel can't find a way to talk to the port if it's
in polling mode(I had this happen before).

in 2.2.x kernel

echo "7" >/proc/parport/0/irq

in 2.4.x kernel

modprobe parport_pc irq=7 io=0x378

those are the typical settings for a PC parallel port, you may be
able to get by without specifying the IO address. after running you
should see something like this in the kernel log:
parport0: PC-style at 0x378, irq 7 [PCSPP,TRISTATE]

be sure to remove the module before trying to re-load it.


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