2 standard serial cards != 4 working serial-devices

2 standard serial cards != 4 working serial-devices

Post by Mats Arvend » Wed, 06 Oct 1993 09:01:49


I'm trying to use two standard serial cards with Linux. I ran
into some problem:

I configured them like this:

Card1                   Card2
COM1 0x3f8 irq 4        COM3 0x3e8 irq 5
COM2 0x2f8 irq 3        COM4 0x2e8 irq 7
I've disabled LPT1 and LPT2 on both cards.

And then I run the following rc.serial script

# -------------------------------------------------
# /etc/rc.serial
#       Version 2.01

SETSERIAL="/etc/setserial -b"
PORTS=`echo cua? cua??`
echo -n "Configuring serial ports...."

# Do wild interrupt detection


# These are the standard COM1 through COM4 devices

${SETSERIAL} /dev/cua0 uart 16550A port 0x3F8 irq 4
${SETSERIAL} /dev/cua1 uart 16550A port 0x2F8 irq 3
${SETSERIAL} /dev/cua2 uart 8250 port 0x3E8 irq 5
${SETSERIAL} /dev/cua3 uart 8250 port 0x2E8 irq 7

echo "done."

# ---------------------------------------------------

BUT! It doesn't work (what a surprise). cua0 and cua1
works fine but when I connect a modem to cua2 and cua3
only a few characters gets through (sometimes nothing).

This must be some form of IRQ-conflict, right?
Any serial wizard out there?



1. Serial mouse only works during installation in graphics mode, problem with 'serial device driver'

During installation in graphics mode the serial microsoft mouse works.
But when Linux starts the console mouse drivers, the following error
appears: 'LSR Safety check engaged!', meaning that the UART 16550A
returns 0xFF to a query of the serial device driver which then
concludes that there is some problem. Result: no serial mouse or
whatever device on the serial port will work.
Now I looked for this problem in google and found
as an explanation: a sloppy designed UART 16550A chip...
My question: is there any updated driver somewhere in which this
problem is resolved?
Or is there any parameter that I can apply during start up to prevent
the serial driver from performing this check?

thanks a lot,

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