Hi.  I have a Quadra 650 that has been clock-chipped to run at 42 MHz.
Everything works well ( no panics, no unusual messages in /var/log/messages
) _except_ the serial ports.
On an ordinary 040 kernel, and when I try to use the serial ports, I get
/netbsd: zstty0 ( or 1 ): fifo overrun anytime I try to use either port.

If I try to start a ppp session with a modem, it can't even get to
establishment.

I increased the ZLRB_RING_SIZE to 1024, and the ZLRB_RING_MASK to 1023, and
I still get fifo overruns, but a ppp session can be established.

My question is: can I continue to increase the ZLRB_RING variables to
numbers such as 2048, 4096, 8192, etc until I find a large enough buffer
size, or is there something else that someone else can think of that would
fix this problem?

Thanks,
Steve