Linux Kernel Sound Driver for Cirrus Logic CS8409 (e.g. for iMac27 5k)
I had the same issue for a long time, and solved it yesterday by install the Sound Driver for Cirrus Logic CS8409 for iMac27-5k 14 from github.
get the kernel version: uname -r Install package linux-headers, select the same version with kernel (with root user or sudo): pacman -S linux-headers clone the driver code: git clone https://github.com/egorenar/snd-hda-codec-cs8409.git compile the code: cd snd-hda-codec-cs8409 make install the driver (with root user or sudo): make install reboot system. Hope this can help you.
PS: If anyone have the no sound issue on Macbook Pro, maybe this repo Kernel audio driver for Macs with 8409 HDA chip + MAX98706/SSM3515 amps 5 can be a solution.