From: nyet@cco.caltech.edu (n liu) Subject: Using other IRQ's for com ports (was Re: Serial driver issues) Date: 28 Dec 1992 00:29:52 GMT
joergp@gmd.de (Joerg Prust) writes:
>In <1heirvINN3gr@gap.caltech.edu> nyet@cco.caltech.edu (n liu) writes:
>>I pulled off the parallel 1 jumper in a weak attempt to disable the address
>>decoding, but linux still thinks its there.
>>However, the setup did seem to work, but the lpt thing bothers me.
>>So the question here is how to disable the lpt port so com3 and 4 can use
>>irq 5 or 7.
>I tried to reproduce that behavior with a couple of cards, but Linux always
>correctly disregarded the printer port (0.99p1 + CONFIG_AUTO_IRQ).
>Did your card manual sheet state explicitely that no jumper means disabling
>the port?
My manual "sheet" consisted of only the jumper diagram I included in the orginal
post - the fact that linux STILL thinks the parallel port is there would
indicate that merely no jumper on the address selection is not enough to
disable it. So I assume that unless there is another component to "disabling"
lpt's (apart from irq and address decoding), the card is now simply decoding
not only the correct lpt1 addresses, but other random addresses as well.
If this is the case, I have no way of disabling it short of finding a schematic
diagram of the card showing how the address lines are used for chip select and
clipping traces :-(
In any case, I have long since given up on the i/o card and will eventually buy
a smarter one.
-- nyet@cco.caltech.edu