[alsa-devel] [PATCH 2/2] ALSA: hda - reduce msleep time if EPSS power states supported

[Wang Xingchao]

if EPSS supported, transition from D3 state to D0 state in less
than 10ms

Signed-off-by: Wang Xingchao <xingchao.wang at intel.com>
---
 sound/pci/hda/hda_codec.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index b89c8ec..5298ba1 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -3526,14 +3526,18 @@ static bool snd_hda_codec_get_supported_ps(struct hda_codec *codec, hda_nid_t fg
 static void hda_set_power_state(struct hda_codec *codec, hda_nid_t fg,
 				unsigned int power_state)
 {
+	bool epss;
 	if (codec->patch_ops.set_power_state) {
 		codec->patch_ops.set_power_state(codec, fg, power_state);
 		return;
 	}
 
+	epss = snd_hda_codec_get_supported_ps(codec, fg, AC_PWRST_EPSS);
 	/* this delay seems necessary to avoid click noise at power-down */
-	if (power_state == AC_PWRST_D3)
+	if ((power_state == AC_PWRST_D3) && !epss)
 		msleep(100);
+	else
+		msleep(10);
 	snd_hda_codec_read(codec, fg, 0, AC_VERB_SET_POWER_STATE,
 			    power_state);
 	snd_hda_codec_set_power_to_all(codec, fg, power_state, true);
-- 
1.7.9.5