ALSA: hda - Check the activity of the NID to be powered down

When an inactive path is powered down with spec->power_down_unused
flag, we should check the activity of each widget in the path whether
it's still referred from any active path.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

path: root/sig.h

#ifndef SIG_H
#define SIG_H

extern void register_signal(int signal, void (*handler)(int));
extern void register_signal_f(int signal, void (*handler)(int), int flags);

#endif /* SIG_H */