> From: David Jones <dej@eecg.toronto.edu>
> Date: 	Wed, 9 Aug 1995 11:33:12 -0400

> I get the "zs1b: fifo overrun" too.  zs1b is the mouse, and the message
> appears as soon as I touch the mouse.  It does not appear at all thereafter.

It sounds like the chip is not being fully cleared-out during open.
We might have some hope of fixing this given a way to reproduce it.
Can anyone describe how to make the overflow happen?

> NetBSD is notoriously poor at serial I/O, but I think there's something
> else here.  The mouse is no more than 9600 bps, which even NetBSD should
> be able to handle.  Most likely something is not properly initialized
> on zs1b at boot.

I'm not sure that's fair as a general statement.  There may be problems
on the i386 port with unbuffered UARTs, but the Sun3 and sparc should
both preform quite reliably for the speeds they support.  The zs chip
is a buffered UART and the driver uses a two-level interrupt scheme
with a ring buffer that makes dropped input very unlikely.

Gordon