Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 28 May 1998 19:58:57 -0400
From:      Dan Swartzendruber <dswartz@druber.com>
To:        freebsd-questions@FreeBSD.ORG
Subject:   reading from serial port?
Message-ID:  <3.0.5.32.19980528195857.00930100@mail.kersur.net>

next in thread | raw e-mail | index | archive | help

I have a null modem cable connecting S0 on two freebsd 2.2.6-stable boxes.
One of the is booted in serial console mode.  I am trying to read from the
serial port on the other one.  I'm seeing some peculiar behavior.  Basically,
when the reader opens /dev/cuaa0 (or /dev/ttyd0), it blocks.  Okay.  Then, if
I throw something in the other end (manually, by 'echo xxx > /dev/cua00', I do
see that output show up, but then the reader goes into an infinite loop of
returning from read with nbytes of zero.  Even though there is clearly no data
present, it is returning nonetheless.  If I close and re-open the port, I do
block as expected.  What am I missing?



To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3.0.5.32.19980528195857.00930100>