🚀 go-pugleaf

fwtk@niw.cerberus.navy.gov.au wrote:
: Can anyone offer me some pointers on this one please?
I hope so ...

: I am using a Linux box as an Internet gateway for a LAN and some dial-in
: lines.  The box has two internal 14.4kbps modems and one external 28.8
: kbps modem.  Two lines are for dialling in and on to dial out to the
: ISP.
: If I use one of the 14.4 kbps modems to dial the ISP I get a download
: speed of around 1000-1300 bytes/sec.  I think this is pretty
: reasonable.  However, when I try to use the 28.8 kbps modem to dial the
: ISP (preferable) the download speed drops to between 100-200 bytes/sec!
: ie, about 10 times SLOWER :-(
: I think it must be the serial card, but it is a new serial card with
: 16550 UARTS.  I have tried configuring it at boot time with:
This sounds like an interrupt conflict to me. More than two serial ports, and
an internal modem is a serial port, are always difficult (there recently was
a thread about this somewhere in comp.os.linux.* land). So check your
interrupt settings. If you use standard settings you will probably have
 ttyS0 IRQ 4
 ttyS1 IRQ 3
 ttyS2 IRQ 4 (!!!)
Most PC cards are not designed to share interrupts, but it is possible
though. If you can avoid shared interrupt whereever possible.

: Thanks,   Ian.
CU
  nils

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Nils Faerber wrote:
> 
> fwtk@niw.cerberus.navy.gov.au wrote:
> : Can anyone offer me some pointers on this one please?
> I hope so ...
> 
> : I am using a Linux box as an Internet gateway for a LAN and some dial-in
> : lines.  The box has two internal 14.4kbps modems and one external 28.8
> : kbps modem.  Two lines are for dialling in and on to dial out to the
> : ISP.
> : If I use one of the 14.4 kbps modems to dial the ISP I get a download
> : speed of around 1000-1300 bytes/sec.  I think this is pretty
> : reasonable.  However, when I try to use the 28.8 kbps modem to dial the
> : ISP (preferable) the download speed drops to between 100-200 bytes/sec!
> : ie, about 10 times SLOWER :-(
> : I think it must be the serial card, but it is a new serial card with
> : 16550 UARTS.  I have tried configuring it at boot time with:
> This sounds like an interrupt conflict to me. More than two serial ports, and
> an internal modem is a serial port, are always difficult (there recently was
> a thread about this somewhere in comp.os.linux.* land). So check your
> interrupt settings. If you use standard settings you will probably have
>  ttyS0 IRQ 4
>  ttyS1 IRQ 3
>  ttyS2 IRQ 4 (!!!)
> Most PC cards are not designed to share interrupts, but it is possible
> though. If you can avoid shared interrupt whereever possible.


You might also want to make sure you're running
'setserial' at boot time.  I've got 4 serial ports,
at IRQ 4, 3, 7, and 11.  Even though they're all
on separate IRQs I was getting miserable results
until I ran setserial set to autoprobe everything
in my /etc/rc.d files (slackware distribution).
Once setserial ran everything was peachy-keen.

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