sof test

In newer devices, the same HDAudio controller can handle both local accessories and HDMI/DP interfaces. However, SOF is not always supported on those platforms.

When the Intel DSP is not enabled in the BIOS (OEM choice), audio interfaces are handled by the snd-hda-intel driver. The platform only exposes PCM devices and no audio processing capabilities.

 

When OEM platforms integrate digital microphones attached directly to the Intel chipset (aka DMIC), or they use I2C/I2S or SoundWire interfaces, the DSP must be enabled by the BIOS. There is, however, one more option. On Skylake and Kaby Lake platforms, the Intel DSP is handled by the snd-soc-skl module which relies on closed-source firmware.

 

SOF is available on Intel PCI devices starting with Gemini Lake, and has since been the only solution provided by Intel for the following platforms: Comet Lake, Ice Lake, and Tiger Lake.

 

Since multiple drivers can register for the same PCI ID, it was (until recently) common for users and distributions to use the wrong driver, which could only be resolved by changing the Linux .config file or deselecting drivers in the /etc/modprobe.d configuration files.

 

The snd-intel-dspcfg module introduced in early 2020 exposes an API used by all drivers, and the user can now override default choices by setting the dsp_driver parameter. For example, setting

 

 

options snd-intel-dspcfg dsp_driver=1

will allow for the HDaudio legacy driver to be used. This will typically work for speakers and headphones/headsets, but will not allow DMIC capture.

 

Conversely, when a platform does not require a DSP-based platform, but the DSP is still enabled by the OEM, the user or integration can force the SOF Linux driver to be used.

 

options snd-intel-dspcfg dsp_driver=3

 

 

snd-intel-dspcfg.dsp_driver=3

 

 

 

nvme.sgl_threshold=1

 

https://linux-hardware.org/?probe=cc2dcd8258&log=lsmod

 

firmware file

/lib/firmware/intel/sof/sof-tgl.ri

contains all DSP code and tables. 

 

 

Topology file

/lib/firmware/intel/sof-tplg/sof-hda-generic-2ch.tplg

describes the processing graph and controls to be instantiated by the SOF driver

 

UCM file

/usr/share/alsa/ucm2/sof-hda-dsp/

  configures the controls exposed by the topology file and the external audio chips. UCM can be used in a terminal via the alsaucm command but will typically be used by audio servers such as PulseAudio or PipeWire. UCM files released by Intel are compatible with different drivers and should work when changing the dsp_driver parameter. The selection of firmware, topology, and UCM files is based on platform capabilities, codec names, and DMI options. 

 

 

errors will happen when the wrong file is selected at any of the three layers.