[U-Boot] [PATCH v2] NS16550: buffer reads

[Simon Glass]

Hi,

On Sun, Oct 23, 2011 at 4:30 PM, Graeme Russ <graeme.russ at gmail.com> wrote:
> Hi Wolfgang,
>
> On Monday, October 24, 2011, Wolfgang Denk <wd at denx.de> wrote:
>> Dear Graeme Russ,
>>
>> In message <
> CALButCJH8BVzfVh14D83WR2JOV89O9jvJO9VzzB7r_ZgKzZqeg at mail.gmail.com> you
> wrote:
>>>
>>> > Problems happen only with multi-line input, so it is perfectly fine
>>> > to handle just that - at the root cause, i. e. when input turns into
>>> > multi-line input.
>>>
>>> Can the U-Boot command line handle multiple commands per line (delimited
> by
>>> ; for example)
>>
>> Yes, it can.
>>
>>> If so, could it not be possible that a Kermit/ymodem command followed by
> a
>>> time consuming command on the same line cause lost input?
>>
>> I don't think so.  All serial transfers use a protocol - and when the
>> transfer is complete, it does not matter any more, because no more
>> data are flowing.
>
> My point is that the transfer turns off flow control - When the transfer
> completes, flow control will be off when the next command begins to run.
> If the next command is one which takes a long time to execute and it is on
> the same line as the transfer command (i.e. no \r to send XOFF) and the
> user types something then that input can be lost.
>
> I think the solution is fairly trivial though - During the processing of
> commands entered via readline(), cause an XOFF to be sent each time (i.e.
> immediately before) the command string is dispatched a to the command
> processor just in case the previous command called getc() (and thus caused
> an XON to be sent)

I had a go at a patch for this, will send out tomorrow. It will need
fixing up for xmodem etc. So far it works ok with minicom but not
ser2net. It is pretty simple.

I think Albert mentioned that XON/XOFF was invented in 1962. Maybe it
will come back into fashion? Not at all sure it will...

Regards,
Simon

>
> Regards,
>
> Graeme
>
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