Re: Cmd/mmap with realtime

On Sat, Nov 09, 2002 at 11:30:49AM +0100, Tomasz Motylewski wrote:
> BTW. There should be an option to avoid the obligation to mark the data as
> read.

Show me the code.  It should be clear that I'm not going to do this
myself, as I don't even have the time to fix many of the obnoxious
bugs that people post to the list.

I haven't been impressed with any of the patches you've sent me
so far.  I get the impression that you want to fundamentally
change the way Comedi works internally, which _isn't_ going to
happen.  Clean additions _are_ useful, however.  This means that
1) it doesn't require significant changes to very many drivers
and/or there's an obviously correct fix for each affected driver,
and 2) it can be cleanly turned on and off, for example, by a
command flag.

There's a possibility that a few of the drivers will require
tweaking to do what you want, but this will generally be cleanup
that should be done anyway.

Also, I tend to be slow applying patches.

> I believe that when using circular buffer the handling of "read
> pointer" is part of the application (or the library for the convinience),
> not the driver.

This leads to race conditions.  Besides, what you believe is not
compatible with the existing Comedi ABI.

> Additional reason for NOT using a function which marks the data as
> read: it adds vulneralibility to future API changes. What is not used can
> not get broken ;-)

What future API changes?  In case you haven't noticed, Comedi and
Comedilib have been (upwardly) API and ABI compatible for about 3
years.  Kcomedilib is a separate issue, since there was a big
change recently to make it source compatible with Comedilib.



dave...

Received on 2002-11-09Z22:36:17