Re: Very strange data loss with jsm driver

From: Lennart Sorensen
Date: Tue Aug 02 2011 - 10:24:03 EST


On Tue, Aug 02, 2011 at 10:22:25AM -0400, Lennart Sorensen wrote:
> On Tue, Aug 02, 2011 at 11:17:52AM -0300, Breno Leitao wrote:
> > Well, I finally tested it over here, and what I found is:
> >
> > If the line has a \r among the first 16 bytes, then the information
> > is TXed immediately. If there is no \r in the first 16 bytes, then the
> > information seems to be buffered.
>
> Where in the driver is this happening?
>
> > So, it seems that that the patch should ask the driver to TX the
> > information when we receive a \r or when the buffer is full. Does it
> > make sense to you ?
>
> Not sure. I just wonder why the data is disappearing rather than getting
> buffered somewhere. Clearly the other serial drivers are doing that
> successfully.
>
> I don't even know why the driver should care about the contents at all.
> Just send data when it is ready.

Also, do you have any idea how to fix the statistics that 2.6.37 broke?
/proc/tty/driver/jsm used to show TX/RX and such, and that stopped
working. I managed to fix it on Debian's 2.6.32 kernel which has some
2.6.37 serial stuff backported, but the same fix didn't work on 3.0.0.

--
Len Sorensen
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