ALSA: hda - introduce snd_hda_codec_update_cache()

Add a new helper, snd_hda_codec_update_cache(), for reducing the unneeded
verbs.  This function checks the cached value and skips if it's identical
with the given one.  Otherwise it works like snd_hda_codec_write_cache().

The alc269 code uses this function as an example.

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

1 files changed, 3 insertions, 0 deletions

diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
index b75da47571e6..49e939e7e5cd 100644
--- a/sound/pci/hda/hda_codec.h
+++ b/sound/pci/hda/hda_codec.h
@@ -885,9 +885,12 @@ int snd_hda_codec_write_cache(struct hda_codec *codec, hda_nid_t nid,
                               int direct, unsigned int verb, unsigned int parm);
 void snd_hda_sequence_write_cache(struct hda_codec *codec,
                                   const struct hda_verb *seq);
+int snd_hda_codec_update_cache(struct hda_codec *codec, hda_nid_t nid,
+                              int direct, unsigned int verb, unsigned int parm);
 void snd_hda_codec_resume_cache(struct hda_codec *codec);
 #else
 #define snd_hda_codec_write_cache       snd_hda_codec_write
+#define snd_hda_codec_update_cache      snd_hda_codec_write
 #define snd_hda_sequence_write_cache    snd_hda_sequence_write
 #endif