diff options
| author | Takashi Iwai <tiwai@suse.de> | 2009-07-22 12:39:24 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2009-07-22 12:39:24 +0200 |
| commit | 05ff7e11b78f18ff6819d2c260b7bcc7da0c8f46 (patch) | |
| tree | d19b9ea9530321a0513863ccd32cf5f3f3f3e343 /sound/pci/hda/hda_codec.c | |
| parent | 05e870d29aef0bf43124b2bd424103987fadd5b5 (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/hda_codec.c')
| -rw-r--r-- | sound/pci/hda/hda_codec.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c index d686f4fcd78..3ecb45ddadf 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++) { |