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authorTakashi Iwai <tiwai@suse.de>2009-07-22 12:39:24 +0200
committerTakashi Iwai <tiwai@suse.de>2009-07-22 12:39:24 +0200
commit05ff7e11b78f18ff6819d2c260b7bcc7da0c8f46 (patch)
treed19b9ea9530321a0513863ccd32cf5f3f3f3e343 /sound/pci/hda/patch_sigmatel.c
parent05e870d29aef0bf43124b2bd424103987fadd5b5 (diff)
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>
Diffstat (limited to 'sound/pci/hda/patch_sigmatel.c')
-rw-r--r--sound/pci/hda/patch_sigmatel.c14
1 files changed, 14 insertions, 0 deletions
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 &