Re: How to avoid serial port buffer overruns?

From: Paul Fulghum
Date: Wed Aug 16 2006 - 18:22:05 EST

On Wed, 2006-08-16 at 17:12 -0400, Lee Revell wrote:
> 2.6.15 and 2.6.16. Here is the .config:

Alan's rework of the receive tty buffering went
into 2.6.16 and cured some problems, but clearly not yours.
Some more adjustments are in 2.6.18-rc4, so that
would be interesting to try for diagnosing this.

I was wondering if the problem was interrupt latency,
the tty receive buffering, or something totally different.
I don't know if your problem and Raphael's are caused
by the same mechanism. I would still like to know which
kernel versions he has tried.

Does the MIDI device using the standard N_TTY line discipline?
Are you using the low_latency flag on the serial device?
What type of UART has been tested (16550? other?)
Are you seeing overruns or just lost data?


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