dgilbert@jaywon.pci.on.ca (David Gilbert) wrote:
>> 	Having got a pc with 16550's for the express purpose of
>> driving serial ports at high speed, I am a tad dismayed that I'm
>> getting silo overflows on the system.

and  jm replied:

> Me too, me too. :-(  My system is a P120 with 16550a UARTs.  I get
> _lots_ of FIFO overruns at 57600 bps with PPP.  I was going to run
> at least six ports at this speed, but using one causes way too many
> errors already. :-(

> Any ideas?

Easy, use the fast interrupt hooks that are still present in the
i386 specific kernel files. My own driver using those hooks did 115200
bps zmodem transfers on a null modem cable using 16450's without dropping
a bit. If there's enough interest I'll update the driver to -current.

On 'nearly' the same topic: Charles changed the transmitter part of com.c
to fix a race condition by only enabling the TX intr bit when needed.
Ever since that change my first ppp-start after powering on my computer
and modem 'hangs'. Yes, the DTR and OH modem leds are switching on but the
dialing process never starts. After killing that process and retrying
ppp-start things work as expected. Anyone else seen this ?

Onno van der Linden (onno@simplex.nl)