Fedora Preparing To Switch To Intel's Modern "Sound Open Firmware" Audio Driver

Fedora 34 is planning to switch to using Intel's modern Sound Open Firmware audio driver as it should be in good shape now and superior to the existing sound driver. This is ahead of Intel likely switching to the Intel SOF driver code path by default in the upstream kernel once this change has first been vetted by Fedora users.

The past few years Intel has been developing Sound Open Firmware. As implied by the name, the sound firmware is now open-source for the audio DSP with this effort. This effort around Intel's Low Power Engine (LPE) began with Bay Trail / Cherry Trail era devices and the SoF effort has continued to more recent hardware. The current default of the upstream kernel and other distributions is to use the existing "SST" firmware solution while the plan is to transition over to using the open-source SoF solution with its modern driver. (There is a separate kernel driver for each firmware solution as opposed to just changing out a proprietary firmware blob for open-source firmware.)

Intel is hoping to eventually deprecate and remove the existing SST default driver for supported Intel LPE audio hardware. But first Fedora will change the driver default there to help in testing before the widespread change in the upstream kernel. This change is made possible by Linux 5.11 now allowing both SST and SOF drivers to be built into a single kernel and to then change the default driver at run-time based on kernel parameters.

Details on the change for Fedora 34 can be found via the Fedora Wiki. The change should be mostly invisible to end-users besides now enjoying open-source sound firmware (BSD/MIT licensed) with Intel LPE hardware and also some issues being resolved with the new driver lie better suspend/resume handling.

More details on the Intel Sound Open Firmware project via this 2019 presentation (PDF).