Working to make ALSA work on a gemini lake tablet

[Sergio Callegari]

Hi,

I am trying to understand the issues that ALSA has on a recent gemini 
lake tablet (the CHUWI HI 10 X) for which otherwise linux support is in 
rather good shape.  In case I am successful, I'd be glad to try to set 
up a guide for users encountering the same or a similar setup.

On this machine, even on very recent kernels, it is impossible to have 
the soundcard recognized (only HDMI audio outputs are shown for aplay -l).

The tablet advertises Intel SST and to the best of my understanding that 
implies that in addition to the basic Intel HDA support there should be 
some codec chip that needs support too (this used to be the bytcrrt5651 
in a previous version of the tablet not based on gemini lake). I also 
see that in many similar pieces of hardware, regular (non HDMI) audio 
support can only be activated by setting some GPIO outputs (e.g., 
https://github.com/danielotero/linux-on-hi10/issues/8).

My biggest element of concern at this point is that I am not able to 
identify the CODEC part, nor to understand if some specific UCM file or 
firmware file is needed.

I wonder if anybody could point me to some hints at how to properly 
identify the hardware and the issue. I have windows pre-installed on the 
system but even from there I have so far been unable to identify the 
audio chipset properly.

Thanks for the attention and even more thanks for any help,

Best,

Sergio