Re: Very strange data loss with jsm driver

From: Lennart Sorensen
Date: Fri Jul 29 2011 - 14:06:54 EST


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
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