serial search reserves IO ports...

serial search reserves IO ports...

Post by Bria » Sun, 31 Dec 1899 09:00:00


I am trying to set up Motorola ISA 56K PnP modem.

I have run "pnpdump --config > isapnp.conf" and the resulting files has
selected a likely I/O that falls in the range set aside for com3 "03E8-03EF"
and IRQ 15.

The problem is something during the boot process "Kernel 2.2.11"
autpmatically reserves that area for "Serial".

My motherboard only has com1 enabled.

rc.serial does not run during boot but something is detecting the serial
port ttyS0 early on during the boot process.

What during boot is automatically reserving all the serial I/O space? (as
seen is /proc/ioports)

How do I defeat this feature?

Thanks for the help.


1. Serial port io too slow!

I have a slight problem with a custom installation of Yggdrasil Linux
1.1.0 (summer release) and it's handling of serial ports.

The io for all four ports, when hooked to either modem or directly to a
terminal is very slow: It takes 15 to 45 seconds for characters to be
sent to or received from the uarts, all 16550A's. It seems as though 16
bytes at a time are being written to the uarts. Received chars often produce
overrun errors.

I have a Quickpath Plexport 4-port serial card with each port set up thus:

        Port 1 (COM1:) io: 0x3f8 IRQ  4 msmouse device 1200 baud
        Port 2 (COM2:) io: 0x2f8 IRQ  3 trailblazer + 19200 baud
        Port 3 (COM3:) io: 0x3e8 IRQ 10 USR Sportster 19200 baud
        Port 4 (COM4:) io: 0x2e8 IRQ 11 local direct 19200 baud

The kernel seems to have been set up for the AST Fourport which is using
IRQ 4 for ports 1 & 3 and IRQ 4 for ports 2 & 4. This according to the info
in /etc/boot.log.

During install, all four ports were detected but the modem test failed to
detect the modems on two of the ports.

I used setserial to change the IRQ assignments. `setserial -ag /dev/ttyS[0-3]'
shows that the IRQ's, ports nad other information is correct.

Setserial is used in /etc/rc.local:
        /bin/setserial /dev/ttyS0 irq 4 uart 16450
        /bin/setserial /dev/ttyS1 irq 3 uart 16550A
        /bin/setserial /dev/ttyS2 irq 10 uart 16550A
        /bin/setserial /dev/ttyS3 irq 11 uart 16550A

TTYS0 is set for 16450 because it is supposed to be a mouse port and I don't
want FIFO's. Even when set as a 16550A and used with a terminal, it has the
same behaviour as the others.

Most of the options and arguments listed in setserial's man page also do
not seem to work: Using any except the ag switches, the port, irq and uart
options result in "invalid argument" errors.

All the ports are monitored by agetty, except port 1 of course. But io
is slow even when login has completed. Uucp is also too slow and one side
or the other times out and gives up.

I cannot use X & control_panel to do anything: the server dies without
giving a clue, though the client seems to work just fine. The server does
work in demo mode when Linux is _not_ installed.

What's going on here??? Any fixes?

Box 51067 Pacific Grove, CA, 93950-6067 USA

2. Strange behavior of SMP Linux 2.2.1

3. serial port io

4. Can't untar apache file

5. Boca IO 2 by 4 (using all 4 serial ports, irq 2)

6. Help needed on listing all processes

7. Asynchronous IO for serial port on Linux

8. Scsh (a Unix Scheme shell) FAQ

9. serial port IO

10. Serial IO: How do I allow two progs to acess the same port????

11. FAQ? sh: redirect io to/from serial port

12. how use 4 serial ports on 2 multi-io cards?

13. Boca IO 2 by 4 (using all 4 serial ports, irq 2)