Hi,

We have a need for our process to poll/monitor the sound cards. This process needs to provide a unique id for the sound card (e.g. some concat of name+hardware address) which we can get using snd_ctl_t handle.

However, we also need to provide the number or rx/tx channels each sound card provides. Doing this using the pcm hw_params after snd_pcm_open won't work as the device may be in use.

Is there a way for this process to get the number of rx/tx channels without needing to 'open' the device, e.g. using the snd_ctl_t handle?

One observation I have made is that there is a proc file ( cat /proc/asound/card1/stream0) that seems to only be populated by the USB soundcards I have and not the Intel builtin. This has all the information I require but if it isn't a standard file we can't rely on it.

Thanks