Re: 2.6.16 serious consequences / GPL_EXPORT_SYMBOL / USB drivers of major vendor excluded

[Steven Rostedt <rostedt@goodmis.org>]

On Sun, 19 Feb 2006, Sasha Khapyorsky wrote:

> On 15:24 Thu 16 Feb     , s.schmidt@avm.de wrote:
> > We are pleased to note that the GPL_EXPORT_SYMBOL fix has been withdrawn.
> > This is particularly important for customers who have been relying on good
> > driver coverage for ISDN/DSL devices with SUSE distributions over the past
> > few years. However, as we understand the ongoing discussion, a number of
> > people are tending towards a position of enforcement of USB GPL drivers
> > only. We would like to take this opportunity to clarify where we see the
> > differences between AVM and other devices and the difficulties regarding a
> > possible move towards user mode.
> >
> > The user space does not ensure the reliability of time critical analog
> > services like Fax G3 or analog modem emulations. This quality of service
> > can only be guaranteed within the kernel space.
>
> Soft modems may work pretty well in userspace - slmodem is example.
>
> Real-time requirement for V.34 is 40ms response time and only once during
> the session when echo canceller parameters are negotiatiated (so you may
> decrease "buffer size" before and increase after - there are enouph
> silence places for such manipulations). Fax itself does not require any
> "realtime" AFAIK, other place is almost unused today V.32 - 26ms, also
> for echo canceller setup.
>

Disclaimer:  This is in no way a push to get the -rt patch into mainline
at the moment.  The patch is still young and is not ready yet.

but...

I would be really interested in knowing how much better a user side driver
can work with the -rt patch implemented.  I bet it can do rather well.

-- Steve

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