Thanks for your comments, rkomar!
Originally Posted by rkomar
Keep in mind that Sony may not have the rights to distribute that source code if they are licensing it from someone else. It would be best to deal with them politely to find more out before letting the accusations fly. The problem may really be due to someone else.
IANAL, but according to my understanding of the GPL, if it were true that the missing kernel module is a Linux-derivative work (according to the definition I cited) and therefore falls under the GPL, and moreover if Sony were prohibited from distributing its source code, then Sony could not distribute the module at all (not even in binary form).
I'd love to get a clarification from Sony. Can you suggest a good avenue for having that discussion with Sony?