ALSA: hda - Reduce click noise at power-saving

Add some tricks to reduce the click noise at powering down to D3
in the power saving mode on STAC/IDT codecs.
The key seems to be to reset PINs before the power-down, and some
delay before entering D3.  The needed delay is significantly long,
but I don't know why.

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

2 files changed, 21 insertions, 2 deletions

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index d686f4fcd780..3ecb45ddadf7 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -2367,9 +2367,14 @@ static void hda_set_power_state(struct hda_codec *codec, hda_nid_t fg,
         hda_nid_t nid;
         int i;
 
-        snd_hda_codec_write(codec, fg, 0, AC_VERB_SET_POWER_STATE,
+        /* this delay seems necessary to avoid click noise at power-down */
+        if (power_state == AC_PWRST_D3)
+                msleep(100);
+        snd_hda_codec_read(codec, fg, 0, AC_VERB_SET_POWER_STATE,
                             power_state);
-        msleep(10); /* partial workaround for "azx_get_response timeout" */
+        /* partial workaround for "azx_get_response timeout" */
+        if (power_state == AC_PWRST_D0)
+                msleep(10);
 
         nid = codec->start_nid;
         for (i = 0; i < codec->num_nodes; i++, nid++) {
diff --git a/sound/pci/hda/patch_sigmatel.c b/sound/pci/hda/patch_sigmatel.c
index 41b5b3a18c1e..00c702df721c 100644
--- a/sound/pci/hda/patch_sigmatel.c
+++ b/sound/pci/hda/patch_sigmatel.c
@@ -4745,6 +4745,20 @@ static int stac92xx_hp_check_power_status(struct hda_codec *codec,
 static int stac92xx_suspend(struct hda_codec *codec, pm_message_t state)
 {
         struct sigmatel_spec *spec = codec->spec;
+        int i;
+        hda_nid_t nid;
+
+        /* reset each pin before powering down DAC/ADC to avoid click noise */
+        nid = codec->start_nid;
+        for (i = 0; i < codec->num_nodes; i++, nid++) {
+                unsigned int wcaps = get_wcaps(codec, nid);
+                unsigned int wid_type = (wcaps & AC_WCAP_TYPE) >>
+                        AC_WCAP_TYPE_SHIFT;
+                if (wid_type == AC_WID_PIN)
+                        snd_hda_codec_read(codec, nid, 0,
+                                AC_VERB_SET_PIN_WIDGET_CONTROL, 0);
+        }
+
         if (spec->eapd_mask)
                 stac_gpio_set(codec, spec->gpio_mask,
                                 spec->gpio_dir, spec->gpio_data &