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ALSA: hda - Reduce click noise at power-saving

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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>
This commit is contained in:
Takashi Iwai 2009-07-22 12:39:24 +02:00
parent 05e870d29a
commit 05ff7e11b7
2 changed files with 21 additions and 2 deletions
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9
sound/pci/hda/hda_codec.c
View file

@ -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++) {

14
sound/pci/hda/patch_sigmatel.c
View file

@ -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 &