From: Marcus Sundberg <marcus@cendio.se>
To: Dan Malek <dan@netx4.com>
Cc: "Brown, David (dbrown03)" <DBrown03@harris.com>,
linuxppc-embedded@lists.linuxppc.org
Subject: Re: Is it normal for serial ports to drop characters at the end?
Date: 03 May 2000 22:05:37 +0200 [thread overview]
Message-ID: <veu2gfv1pq.fsf@lipta.cendio.se> (raw)
In-Reply-To: Dan Malek's message of "Wed, 03 May 2000 15:53:48 -0400"
Dan Malek <dan@netx4.com> writes:
> Marcus Sundberg wrote:
>
> > Right on target.
> > rs_8xx_wait_until_sent() will wait for the *first* buffer descriptor
> > to be finished, instead of waiting for the last one as it should.
> > This patch fixes that problem:
>
> That's part of it, but we also need to perform a graceful shutdown
> of the port so we wait until the hardware FIFOs are empty. Waiting
> for the buffer descriptor just means the CPM moved the last data
> from the buffer, not that it has gone out the wire.
Sure, but the above "works perfect for me(tm)", at least in 9600bps.
> I thought I did this once.....but, why are you closing devices anyway :-).
I think I experienced this first when using the busybox init
implementation, which IIRC opens and closes /dev/console for each
message. Otherwise I've never seen it in a real application.
/Marcus
--
-------------------------------+-----------------------------------
Marcus Sundberg | Phone: +46 707 452062
Embedded Systems Consultant | Email: marcus@cendio.se
Cendio Systems AB | http://www.cendio.com
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
prev parent reply other threads:[~2000-05-03 20:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-05-03 15:30 Is it normal for serial ports to drop characters at the end? Brown, David (dbrown03)
2000-05-03 19:27 ` Marcus Sundberg
2000-05-03 19:53 ` Dan Malek
2000-05-03 20:05 ` Marcus Sundberg [this message]
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