Can't connect to internal modem

[Lennart Sorensen]

On Wed, May 16, 2007 at 07:20:28AM -0400, Walter Dnes wrote:
>   My ADSL connection had a short outage during the weekend.  I
> discovered, to my consternation, that my machine's internal modem wasn't
> being picked up.  This is a 1999 Dell PIII that refuses to die.  The PCI
> modem has worked in the past under Redhat and Gentoo.  "lspci -v" shows...
> 
> 00:10.0 Serial controller: 3Com Corp, Modem Division 56K FaxModem Model
> 5610
> +(rev 01) (prog-if 02 [16550])
>         Subsystem: 3Com Corp, Modem Division Unknown device baba
>         Flags: medium devsel, IRQ 9
>         I/O ports at 1430 [size=8]
>         Capabilities: [dc] Power Management version 2
> 
>   It's *NOT* a "winmodem".  It's a bog-standard PCI modem that has
> worked in the past under linux without requiring special drivers.  The
> only tweak it requires is allocating more than 4 serial ports in the
> kernel, which I've done.  Any ideas on kernel settings I might have
> missed?

I think more recent 2.6 kernel changed something in how serial ports
were allocated, so you may need a new parameter to tell it to allocate
more than 4 serial ports.  The kernels I build myself at the moment has
these config options set:

CONFIG_SERIAL_8250_NR_UARTS=36
CONFIG_SERIAL_8250_RUNTIME_UARTS=36

A stock debian kernel on the other hand has:
CONFIG_SERIAL_8250_NR_UARTS=16
CONFIG_SERIAL_8250_RUNTIME_UARTS=4

I think the 'runtime uarts' is the one that you may have hit.

You can increase it with a kernel command line option up to the maximum
of the NR_UARTS value using this command line option:

8250.nr_uarts=XX (where XX is how many ports you want it to look for in
total).

So you can add that to your kernel line in grub's menu.lst or your
append in lilo.conf and it should work.

It used to be that whatever the NR_UARTS was set to was how many ports
it would look for.

--
Len Sorensen
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