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ALSA: hda: Fix max PCM level to 0 dB for AD1981_HP

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BugLink: https://bugs.launchpad.net/bugs/461062

The original reporter states that PCM maxes at +12 dB and results in
very bad distortion.  Cap PCM at 0 dB to resolve this symptom.

Signed-off-by: Daniel T Chen <crimsun@ubuntu.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Daniel T Chen 2009-12-13 16:22:58 -05:00 committed by Takashi Iwai
parent 950200e2ff
commit 01f5966d2f
1 changed files with 8 additions and 0 deletions
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8
sound/pci/hda/patch_analog.c
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@ -1789,6 +1789,14 @@ static int patch_ad1981(struct hda_codec *codec)
codec->patch_ops.init = ad1981_hp_init;
codec->patch_ops.unsol_event = ad1981_hp_unsol_event;
/* set the upper-limit for mixer amp to 0dB for avoiding the
* possible damage by overloading
*/
snd_hda_override_amp_caps(codec, 0x11, HDA_INPUT,
(0x17 << AC_AMPCAP_OFFSET_SHIFT) |
(0x17 << AC_AMPCAP_NUM_STEPS_SHIFT) |
(0x05 << AC_AMPCAP_STEP_SIZE_SHIFT) |
(1 << AC_AMPCAP_MUTE_SHIFT));
break;
case AD1981_THINKPAD:
spec->mixers[0] = ad1981_thinkpad_mixers;