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>

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index d686f4fcd780e059fa83c0121a64240a3396b663..3ecb45ddadf7f6710df320a421c6d45f2d76aeda 100644 (file)
--- 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 41b5b3a18c1ee3efcdd910643aaea45e12f59ae1..00c702df721ccd0a0573e8c58b5ffbed778117d3 100644 (file)
--- 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 &