This page contains information about hardware related to sound, potential freedom issues and ways to fix or workaround them.
In many GNU/Linux distributions there is a package called sof-firmware that contain nonfree firmwares: some of the firmwares are signed by hardware manufacturers and the hardware enforces signature checking, so that makes them nonfree as users can't run modified versions of these firmwares.
Part of the documentation mentions that:
Firmware binary signing is for audio DSP is mandatory on Intel products from Skylake onwards. i.e. no code signing on Baytrail, Cherrytrail, Braswell, Haswell and Broadwell but mandatory on Skylake, Kabylake, Apollolake, Cannonlake Icelake and Tigerlake.
But this also means that if we build the firmwares and ship them in FSDG compliant distributions, they might work on Intel computers before skylake that need them. There is also other non-intel related firmwares that might could with free software.
- Audit the source code and add them respective projects to the free software directory, and like with the wine article, add a warning that some of the binary firmwares are nonfree and that the free software directory doesn't review binaries anyway.
- Try to build and run the firmwares and run them on intel computers before skylake and/or on other supported sound DSP.