Make audio work on cx2072x devices like the Asus E200HA

Good News everyone!

Starting with Version 5.3, the default linux kernel will support the cx2072x (see this commit)
This means that installing this custom patched kernel will now longer be required if you already use kernel 5.3 or newer!
You'll probably still need the alsa-ucm files, but this is great because it massively simplifies the installation and reduces the possibility of problems

TL;DR

If You're on Debian or Ubuntu, run this (at your own risk!!)

wget -qO- https://gist.github.com/heikomat/3fe272431b44b580c933bfb901a92257/raw | bash

General sound setup:

Most of the following information are from these sources:

• Kernel Bug #115531
• Repository with the Fixes
• Asus E200HA fix-script-Repo by Grippentech

This manual is for debain and derivates of it, though it can probablydefinitely be adapted for other linux systems (see here). Debian and Ubuntu users can use the script provided above. Its goal is to do the steps described here:

1. Get the Kernel with the cx2072x codec driver and the cx2072x machine driver from releases, or build it yourself (see building the kernel)

   This tells the Linux how to talk to the hardware.

2. Install the kernel

   sudo dpkg --install LINUX_IMAGE_DEB_PACKAGE.deb
   sudo dpkg --install LINUX_HEADERS_DEB_PACKAGE.deb
   

3. Have pulseaudio installed

   sudo apt install pulseaudio

4. Have firmware-intel-sound (for debian) or linux-firmware (for ubuntu) installed.

   This contains the firmware for intels sst audio device (/lib/firmware/intel/fw_sst_22a8.bin). The firmware is the proprietary software that runs within the chip.

   # debian
   sudo apt install firmware-intel-sound
   
   # ubuntu
   sudo apt install linux-firmware

5. Copy the configuration files for alsa (bytcht-cx2072x.conf and HiFi.conf from the bytcht-cx2072x folder) to /usr/share/alsa/ucm/bytcht-cx2072x (creating the folder first).

   These tell alsa what driver and codec to use, and how to use them

   sudo mkdir --parents /usr/share/alsa/ucm/bytcht-cx2072x
   cd /usr/share/alsa/ucm/bytcht-cx2072x
   sudo wget "https://raw.githubusercontent.com/heikomat/linux/cx2072x/cx2072x_fixes_and_manual/bytcht-cx2072x/HiFi.conf"
   sudo wget "https://raw.githubusercontent.com/heikomat/linux/cx2072x/cx2072x_fixes_and_manual/bytcht-cx2072x/bytcht-cx2072x.conf"

6. Set realtime-scheduling = no in /etc/pulse/daemon.conf (see this issue-comment).

   This makes the pulseaudio daemon not die if the audio device is not found instantly

   via script

   sudo sed --in-place --regexp-extended --expression='s/;?\s*realtime-scheduling\s*=\s*(yes|no)/realtime-scheduling = no/g' /etc/pulse/daemon.conf

   by hand

   1. Make sure you edit the file as root, for example with sudo nano /etc/pulse/daemon.conf
   2. Change ; realtime-scheduling = yes to realtime-scheduling = no
   3. make sure you removed the ; at the beginning of the line, this is important!

7. Reboot

Possible fixes if audio is still not working:

• Remove possibly existing user-pulse-config with rm -rf ~/.config/pulse/*
• Set pulseaudios default device:
  1. Check wich index your non-hdmi audio device has with pactl list short sinks
  2. pacmd set-default-sink 1 (replacing the 1 with the audio-device-index)

Getting a detailed pulseaudio log, for when debugging is necessary

1. Enable debug-messages for pulseaudio by editing /etc/pulse/daemon.conf
   1. Make sure you edit the file as root, for example with sudo nano /etc/pulse/daemon.conf
   2. Change ; log-level = notice to log-level = debug
   3. make sure you removed the ; at the beginning of the line, this is important!
2. Reboot
3. Put a log on the Desktop with

   sudo cat /var/log/syslog | grep 'intel\|cx2072x\|pulse\|alsa\|cht\|byt\|error' > ~/Desktop/pulselog.txt

4. Give use the pulselog.txt you now have on your Desktop