Re: [Linux-usb-users] [SOLVED] Serial buffer corruption [was Re: FTDI usb-serial possible bug]

From: Antonino Ingargiola
Date: Mon May 07 2007 - 04:07:48 EST


2007/5/6, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>:
On Sun, 6 May 2007, Alan Cox wrote:

> > However, whatever policy the buffer uses, the fundamental point it's that
> > when I flush the input buffer I should be sure that each byte read
> > after the flush is *new* (current) data and not old one. This because
>
> Define "new" and "old" in this case. I don't believe you can give a
> precise definition or that such a thing is physically possible.

One can come close. It would make sense to say that after a flush,
subsequent reads should retrieve _contiguous_ bytes from the input stream.
In other words, rule out the possibility that the read would get bytes
1-10 (from some buffer somewhere) followed by bytes 30-60 (because bytes
11-29 were dropped by the flush). By contrast, it would be permissible
for the read to obtain bytes 20-60, even though 20-29 may have been
entered the input stream before the flush occurred.


You've expressed in an extremely clear way what I meant. Thanks.


Regards,

~ Antonio
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