Missing serial port

[Frans Ketelaars]

On Sun, 09 May 2010 08:31:22 +0300, Dotan Cohen wrote:

> A neighbour's computer has five serial ports, one on the motherboard and
> four on a PCI card. However, only four cards are showing:
> 
> # dmesg | grep tty
> [    0.000000] console [tty0] enabled [    0.394565] serial8250: ttyS0
> at I/O 0x3f8 (irq = 4) is a 16550A [    0.394877] 00:08: ttyS0 at I/O
> 0x3f8 (irq = 4) is a 16550A [    0.395080] 0000:03:06.0: ttyS1 at I/O
> 0xcf00 (irq = 20) is a 16550A [    0.395201] 0000:03:06.0: ttyS2 at I/O
> 0xce00 (irq = 20) is a 16550A [    0.395320] 0000:03:06.0: ttyS3 at I/O
> 0xcd00 (irq = 20) is a 16550A [    8.751992] setserial sets custom speed
> on ttyS1. This is deprecated. [    8.754670] setserial sets custom speed
> on ttyS3. This is deprecated. [   70.056749] redhot sets custom speed on
> ttyS3. This is deprecated. [   80.734705] radoga sets custom speed on
> ttyS1. This is deprecated. [ 5437.884113] redhot sets custom speed on
> ttyS3. This is deprecated. [ 5510.465311] redhot sets custom speed on
> ttyS3. This is deprecated. [ 5662.096348] redhot sets custom speed on
> ttyS3. This is deprecated. [ 5692.931148] redhot sets custom speed on
> ttyS3. This is deprecated. #
> 
> The motherboard card is ttys0. All five ports work in Windows, and
> replacing the PCI card with another identical, known good card showed
> the same results. This is Ubuntu 10.04. Any ideas what could be wrong?
> 
> Thanks.

Does http://www.linux.org/docs/ldp/howto/Serial-HOWTO-16.html#ss16.3 help?

    -Frans