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From: lsorense@csclub.uwaterloo.ca (Lennart Sorensen)
To: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
	linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
	Breno Leitao <leitao@linux.vnet.ibm.com>
Subject: Re: Very strange data loss with jsm driver
Date: Fri, 29 Jul 2011 14:06:50 -0400	[thread overview]
Message-ID: <20110729180650.GL8562@caffeine.csclub.uwaterloo.ca> (raw)
In-Reply-To: <20110729165342.GB8566@caffeine.csclub.uwaterloo.ca>

On Fri, Jul 29, 2011 at 12:53:42PM -0400, Lennart Sorensen wrote:
> On Fri, Jul 29, 2011 at 05:27:36PM +0100, Alan Cox wrote:
> > > The trigger point appears to be lines of up to 14 bytes, followed by
> > > a newline.  With 15 bytes or more per line it seems to be OK.
> > > 
> > > Anyone got a clue?
> > 
> > FIFO size perhaps - and some kind of missed wakeup or tx handling bug ?
> 
> FIFO size is 64bytes, so that doesn't immediately sound related.
> 
> The thing I find weird is that it thinks everything was sent right away.
> 
> Also why should the newline have anything to do with it?  If you send
> 100100 bytes should it matter where the newlines are unless the tty
> layer or the driver is interpreting the newlines for some reason.

Same breakage on 2.6.18.  I suspect this has always been broken.

Hmm.

I noticed fifosize in the uart_port info is set to 16, even though the
fifo size is actually 64 bytes as all actual driver bits know.  What is
fifosize actually used for?

-- 
Len Sorensen

  reply	other threads:[~2011-07-29 18:06 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-29 16:04 Very strange data loss with jsm driver Lennart Sorensen
2011-07-29 16:27 ` Alan Cox
2011-07-29 16:53   ` Lennart Sorensen
2011-07-29 18:06     ` Lennart Sorensen [this message]
2011-07-29 18:14       ` Alan Cox
2011-07-29 18:13         ` Lennart Sorensen
2011-08-02 14:17           ` Breno Leitao
2011-08-02 14:22             ` Lennart Sorensen
2011-08-02 14:23               ` Lennart Sorensen
2011-08-02 14:49               ` Breno Leitao
2011-08-02 14:52                 ` Lennart Sorensen

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