[Wylug-discuss] On-board Serial Ports

[Jim Jackson]

Hi Martin,

I've played with serial ports, and don't have instability problems.
I find it pays to make sure they are correctly setup using setserial
at boot time. Then there is no problem. You really need to get the kernel
set to the correct "uart" type. Maybe the autoconfig bit isn't working.

Also make sure nothing else has the IRQ. With modern motherboards and PCI
IRQ conflicts can happen if you haven't got the BIOS set right. Check for
interrupt count increasing in /proc/interrupts when you are not using the
serial ports at all.

Jim


On Thu, 23 Sep 2004, Martyn Ranyard wrote:

>
> Hi All,
>
>   One of the things that has been bugging me for some time now is with
> SBCs and recent motherboards, the onboard com ports seem completely
> unreliable under Linux.
>
>   Taking this to its most bizarre conclusion, we tend to use USB<->RS232
> adapters which work well under linux to connect serial modems.  This may
> seem a strange combination, but is the one which works.
>
>   So, being that onboard ports always seem to get the "standard"* IRQ
> and IO addresses, is there anything I'm missing, I've not messed around
> too much with it, but given the "standard"ness of the ports, the
> instability (feels like irq conflicts) thereof annoys/disturbs me.
>
>   The alternative of course would be to find a good, cheap USB faxmodem,
> and not worry about it.  What's really annoying is that serial mice seem
> to work okay, but modems slow to a crawl.
>
>   Any tips/tricks people have done to get faxmodems working on modern
> onboard serial ports?
>
> --
> Martyn Ranyard
> Development Manager
> Synergistic Software
> (01937) 573 446
> http://www.syn.co.uk/
>
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