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

[Sasha Khapyorsky <sashakh@gmail.com>]

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 We are pleased to note that the GPL_EXPORT_SYMBOL fix has been withdrawn.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.

Regards,
Sasha.