Problem writing device driver for SCO Unix V/386 3.2.0.

david nugent david at csource.OZ.AU
Fri Jun 15 21:57:18 AEST 1990

In <916 at> tih at (Tom Ivar Helbekkmo) writes:

 > Anyway, with SCO's serial driver ("sio"), this won't work.  (Unless
 > I'm mistaken, in which case I'd like to hear about it!)  Each serial
 > port that's not on an intelligent card has to have its own IRQ.

That's not quite true.  SCO supports a few serial cards which aren't
"intelligent" (ie. processor driven) which can share IRQ's.  The Hostess
and DigiBoard (not the COM?/i versions), for example.

The sample sio driver in the documentation is abysmal; when compiled
and linked in - even without modifications and after cleaning up the
typo's - doesn't even work.  It's also quite dated under the current
kernel version and doesn't support everything required (hardware flow
control and additional line disciplines, for example).

 > Because of this, I've been trying to write my own replacement for the
 > supplied sio driver.  I've based it on the example code in the Device
 > Driver Writer's Guide, and followed the guidelines there. 

You're probably asking the impossible of the hardware.  I'm yet to find
a serial card which doesn't advertise that it can share IRQ's (even though
you might be able to switch them independantly) and yet can.  What
this amounts to is that you probably _CAN'T_ share IRQ's on the card
you're using.  It may not have the necessary hardware and logic to do

Sorry - I know it's bad news.  I had to learn the hard way too. :-(

         * Unique Computing Pty Ltd, Melbourne, Australia. *
       david at  3:632/348 at fidonet  28:4100/1 at signet

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