snd_ctl_add_slave_uncached(9) centos man page | unix.com

SND_CTL_ADD_SLAVE_UN(9) 					 Control/Mixer API					   SND_CTL_ADD_SLAVE_UN(9)

NAME
       snd_ctl_add_slave_uncached - Add a virtual slave control

SYNOPSIS
       int snd_ctl_add_slave_uncached(struct snd_kcontrol * master, struct snd_kcontrol * slave);

ARGUMENTS
       master
	   vmaster element

       slave
	   slave element to add

DESCRIPTION
       Add a virtual slave control to the given master. Unlike snd_ctl_add_slave, the element added via this function is supposed to have volatile
       values, and get callback is called at each time quried from the master.

       When the control peeks the hardware values directly and the value can be changed by other means than the put callback of the element, this
       function should be used to keep the value always up-to-date.

RETURN
       Zero if successful or a negative error code.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014						   SND_CTL_ADD_SLAVE_UN(9)