GDPR-2 I think that the idea behind "common Amlogic GX project" is to use mainline kernel and V4L2 interface for HW-accelerated video playback which is yet to be written for Amlogic. GDPR-1 means to upstream the patches we have for current Amlogic state, e.g. 3.14 kernel and amcodec. As soon as I get my new laptop I will start working on upstreaming patches. Thanks to you and afl1 it will be a little easier now that the patches are rebased for Leia.
The patches I uploaded are specific to the S905/X and do not include your S912 changes, I had little interest in that device due to the SW decoding limitation.
I hope the LE team would allow your changes to the linux package to continue using a custom kernel in that case until the changes have been made in the future.