Sound / Audio Entry Point
I am struggling to find some area of code in the kernel that gets executed while audio is playing. My current goal is to be able to find the actual audio data in the kernel and print some of it out to make sure I can actually see audio bytes going through the kernel. Do you know of anywhere in the code that I could insert a printk() and see some data? If not, do you know of any entry point in the kernel sound code that gets executed every time audio gets played?
I would appreciate information about any version of the kernel that you are familiar with, but I am currently using version 18.104.22.168.
I have tried putting printk()s in sound/core/pcm_lib.c in functions like snd_pcm_lib_write_transfer. When playing audio, none of those messages show up, so I'm not really sure where else to look at this point.
Any help is greatly appreciated.