Linux 5.8 To Add Auto-Detection For Using SoundWire On Newer Intel Platforms

While the Linux 5.7 feature merge window just closed yesterday, there is already one feature queued up for Linux 5.8 that caught our eye.

Queued today in the sound subsystem's "-next" branch is auto-detection support for SoundWire. As self-described on the MIPI project page, "MIPI SoundWire, introduced in 2014, consolidates many of the key attributes in mobile and PC audio interfaces, providing a common, comprehensive interface and scalable architecture that can be used to enable audio features and functions in multiple types of devices and across market segments. It supports the use of advanced amplifiers and microphones. In addition, it can also optimize speaker protection, microphone power and performance, noise cancellation and always-listening audio input."

Going back to late 2016, Intel has been working on the SoundWire support for Linux. SoundWire was then merged to Linux 4.16 in early 2018 and has continued to see various SoundWire improvements since that time -- most recently with the SoF SoundWire support getting squared away in Linux 5.7.

Now with Linux 5.8 the SoundWire support looks robust enough that auto-detection code is being added. The code contributed by Intel adds auto-detection support to use SoundWire when available in place of the legacy HDA driver code or Intel's Skylake drivers, sans any particular hardware being quirked to fall-back to the existing driver code paths.

This Intel SoundWire support is in turn built off their Sound Open Firmware initiative. The SoundWire support appears to be in good shape for Intel's latest Comet Lake platform while is also found on some Skylake+ platforms with digital microphones (DMIC) and more broadly on Cannonlake+ platforms.

The auto-detection for using the SoundWire path is now queued in sound for-next ahead of the Linux 5.8 merge window in June.