megi's PinePhone Development Log RSS


2024–02–24: Some upstreaming and Pinephone Pro modem audio

I've been working on upstreaming a bunch of patches for Pinephone (Pro):

There are also large changes in my kernel tree branches organization starting with orange-pi-6.8. The branches are split up differently and more finely. So there are a lot more individual branches that make up orange-pi-6.8 integration branch.

I support/develop for about 14 different boards in my kernel, so if you're interested in just Pinephone you'll have much easier time just merging a subset of branches into your own integration branch, if you don't like having other changes I carry in my kernel tree, in your kernel build.

The orange-pi-6.8 branch now looks pretty good, and I'm already using it regularly on some of my SBCs and on Pinebook Pro.

Pinephone Pro modem audio work

I've managed to create a setup for passing audio between modem's codec and the main codec in the best possible quality. S/N ratio is very good (> 80dB at the very least), and I managed to understand and get rid of sources of the apparent distortion in the signals that I was getting before.

I've made it so both directions use differential signalling at maximum possible signal amplitude to improve the S/N ratio. There's also no apparent interference from the other noise going on on the PCB, according to my tests of this setup.

I'm still working on the main codec audio routing setup to be able to connect the modem signals to mic and earphone properly.

I'll be publishing all my findings on this, including my audio routing setup tools for both codecs, soon. A small patch to the modem SDK will be needed. The „patch“ is applicable over adb access to the modem.

I'll also do some testing on audio issues that may arrise after suspend/resume cycle, because I got reports that there are problems with that.