Adding linux-firmware people to Cc, since presumably they don't
necessarily read linux-wireless...

Johannes, from that perspective, who are the "redistributors"? 

Specifically, is linux-firmware git repository considered a
redistributor or its just hosting files? I mean, at what moment
someone else other then Quantenna will start to be legally obliged to
make GPL code used in firmware available for others?

Look, I don't know. I'd assume people who ship it, like any regular
distro, would be (re)distributors thereof. "Normal" (non-GPL) firmware
images come with a redistribution license, but that obviously can't
work here.

There's some info from Ben here regarding the carl9170 case:
http://lkml.iu.edu/hypermail/linux/kernel/1605.3/01176.html

Personally I still hope that linux-firmware itself is not legally 
concerned with what is the content of firmware its hosting, but looks
like there already was a precedent case  with carl9170 driver and
we have to somehow deal with it.

That's really all I wanted to bring up. I'm not involved with the
linux-firmware git tree.

There still may be a difference though: Quantenna is semiconductor 
company only, software
used on actual products based on Quantenna chipsets is released by
other 
companies.
I just want to present our legal team with a clear case (and position
of 
Linux maintainers) so that they can
work with it and make decision on how to proceed.

 From technical perspective, as I mentioned, SDK is quite huge and 
include a lot of opensource
components including full Linux, I don't think its reasonable to have
it 
inside linux-firmware tree.
What are the options to share it other then providing it on request
basis:
- git repository
- store tarball somewhere on official website

Clearly that wasn't deemed appropriate for carl9170, so I don't see why
it'd be different here.

johannes