From: cummings@bbird8.Prime.COM (Kevin Cummings) Subject: Re: Modems and IRQ's (again) Date: Wed, 28 Oct 1992 16:43:43 GMT
In article <1992Oct28.011033.27165@mnemosyne.cs.du.edu>, chand@nyx.cs.du.edu (Chris Hand) writes:
|> I had modem problems -- turned out I had 2 cards using the same
|> IRQ. Funny thing is under DOS and Windows I had no problems...
Who said that DOS or Windows used the IRQ lines? They usually don't.
The configurations are listed like that so that smarter software can
take advantage of them IF IT WANTS TO. DOS generally doesn't want to.
|> So it looks like serial.c in the kernel code *assumes* that
|> COM1/COM3 are on IRQ4 and COM2/COM4 on IRQ 3. I've now got
|> the modem set to COM3/IRQ5 but at startup I'm told
|> that COM3 is IRQ4.
Yeup, the initial IRQs for the serial ports are hard coded into
a table in the kernel. Use the "setserial" program to make
modification. I do it in /etc/rc.local.
|> Obviously I could patch the kernel (anywhere else apart from
|> serial.c??), but this is no good if I need to swap again
|> (I regularly swap jumpers and strip the PC down...:-).
|>
|> Is there some way we can have an /etc/irqinit or something
|> that we can use to specifiy what devices are using which IRQ
|> lines? I have a MIDI i/f and a scanner board in there and I can see
|> more problems in the future.
|>
|> Chris cph@dmu.ac.uk
|>
|> (if I should be addressing this to some mailing list somewhere please
|> let me know!)
|>
--
=================================================================
Kevin J. Cummings PrimeService
20 Briarwood Road A Computervision Company
Framingham, Mass. 500 Old Connecticut Path
Framingham, Mass.
Work: cummings@primerd.Prime.COM
Home: cummings@kjc386.framingham.ma.us
Std. Disclaimer: "Mr. McKittrick, after careful consideration,
I've come to the conclusion that your new
defense system SUCKS..." -- War Games
=================================================================