[CentOS] How do I configure additional serial ports?

Alfred von Campe alfred at 110.net
Fri Mar 9 17:10:55 UTC 2007

On Mar 9, 2007, at 11:41, Paul Heinlein wrote:

> Still, what leaps out at me in your verbose lspci listings (below)  
> is that the card with PCI ID 0a:0a:[01] (IRQs 177/193) is showing  
> up while card 0a:0c.[01] (IRQs 217/225) isn't showing up at all.
> I don't understand why each card is getting two IRQs, but I'd  
> expect to see something like
>   ttySX at I/O 0xXXXX (irq = 217) is a 16C950/954
> show up in your dmesg. Instead, all the ttySX listings from your  
> dmesg have IRQs from only one of the cards.

Yes, that is the problem.  In another reply, someone mentioned a  
kernel configuration option that may be limiting the number of serial  
ports, which I'll be looking into.

> Have you verified that each card works properly if installed by  
> itself, without the other?

Yes, they both work fine in either PCI slot.


More information about the CentOS mailing list