From: rmarson@rp.CSIRO.AU (Ralph Marson) Subject: Can COM1/2: and COM3/4 be used simultaneously? Date: Wed, 28 Apr 1993 04:09:03 GMT
I have two multi-I/O cards each with two serial ports and one parallel port.
One card has its serial ports configured for IRQ3,4 and IO Port 3F8,2F8
The other card has IRQ3,4 and IO Port 3E8,2E8 (ie. COM1-4 in the 'standard?'
configuration). Under either DOS or Linux I am unable to simultaneously use
two ports which share an interrupt line. From a hardware point of view this
seems reasonable and I should use another of the scarce interrupt lines.
However without cutting tracks etc. I am unable to change the interrupt lines
of either of these cards.
What I want to know is, can Linux be configured to do something clever when
an interrupt occurs on IRQ3 say, so that it polls both serial ports to
see which one has the data?
Of course any other solutions on how to solve this problem are welcome.
Ralph Marson
rmarson@rp.csiro.au
PS. I am using Linux 0.99pl8 and C libraries 4.3.3 on a clone 486/33 (AMI BIOS)