Bug#440807: increase CONFIG_SERIAL_8250_NR_UARTS (number of serial ports)

[maximilian attems <max@stro.at>]

On Tue, Jan 08, 2008 at 02:50:41PM -0600, Lukasz Szybalski wrote:
> 
> Currently we have 1 serial port on motherboard and 2 port pci card. I 
> would like to add another 4 port pci card. I am not able to do it 
> because I get a conflict on ttyS.
> 
> Since regular pc pci limit is on average 3. the max serial ports I could 
> install is  3x(6port serial card)  + 1 on mother board.  So Max I could 
> fit on is 19 if I wanted to. Realistically it would be optimal for me to 
> have  at least 7 available.
> 
> Is there some kind of setting that can be changed without recompiling 
> the  kernel to allow this many serial ports or some kernel header that 
> would increase the number of available serial ports without much problem?

$  egrep NR_UARTS /boot/config-2.6.24-rc7-amd64  
CONFIG_SERIAL_8250_NR_UARTS=16

$  egrep RUNTIME_UARTS /boot/config-2.6.24-rc7-amd64  
CONFIG_SERIAL_8250_RUNTIME_UARTS=4

This can be overridden with the module parameter "nr_uarts", or
boot-time parameter 8250.nr_uarts.

up to 16 evidently

-- 
maks