Mailing list
From Driver Backports Wiki
Use the backports@vger.kernel.org mailing list for patches / bug reports / questions for both compat.git and compat-drivers.git.
Subscribing to backports
The project mailing list is backports@vger.kernel.org. It uses majordomo for management so to subscribe send an e-mail to majordomo@vger.kernel.org with anything on the subject and with this on the body of the e-mail:
subscribe backports
You will receive an e-mail from Majordomo telling you what other steps you need to follow to subscribe.