1. 根目录:
2. include
3. sound
4. hda_i915.h

/*
 * HD-Audio helpers to sync with i915 driver
 */
#ifndef __SOUND_HDA_I915_H
#define __SOUND_HDA_I915_H

#include <drm/i915_component.h>

#ifdef CONFIG_SND_HDA_I915
int snd_hdac_set_codec_wakeup(struct hdac_bus *bus, bool enable);
int snd_hdac_display_power(struct hdac_bus *bus, bool enable);
int snd_hdac_get_display_clk(struct hdac_bus *bus);
int snd_hdac_i915_init(struct hdac_bus *bus);
int snd_hdac_i915_exit(struct hdac_bus *bus);
int snd_hdac_i915_register_notifier(const struct i915_audio_component_audio_ops *);
#else
static inline int snd_hdac_set_codec_wakeup(struct hdac_bus *bus, bool enable)
{
	return 0;
}
static inline int snd_hdac_display_power(struct hdac_bus *bus, bool enable)
{
	return 0;
}
static inline int snd_hdac_get_display_clk(struct hdac_bus *bus)
{
	return 0;
}
static inline int snd_hdac_i915_init(struct hdac_bus *bus)
{
	return -ENODEV;
}
static inline int snd_hdac_i915_exit(struct hdac_bus *bus)
{
	return 0;
}
static inline int snd_hdac_i915_register_notifier(const struct i915_audio_component_audio_ops *ops)
{
	return -ENODEV;
}
#endif

#endif /* __SOUND_HDA_I915_H */