I just tried the 20150903 backports and I didn't have to patch the code (still need to copy the firmware and create /etc/modprobe.d/ath10k.conf.
Also, looking at the code from the backport, the firmware still needs to be copied to QCA6174 (instead of QCA6164). Guess it's getting better (maybe in a few months, there will be no need to do manual work).
I just tried the 20150903 backports and I didn't have to patch the code (still need to copy the firmware and create /etc/modprobe. d/ath10k. conf.
Also, looking at the code from the backport, the firmware still needs to be copied to QCA6174 (instead of QCA6164). Guess it's getting better (maybe in a few months, there will be no need to do manual work).