From 01f5966d2f36f08eb6604665eade69c9f38ffaed Mon Sep 17 00:00:00 2001 From: Daniel T Chen Date: Sun, 13 Dec 2009 16:22:58 -0500 Subject: [PATCH] ALSA: hda: Fix max PCM level to 0 dB for AD1981_HP 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 Signed-off-by: Takashi Iwai --- sound/pci/hda/patch_analog.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/sound/pci/hda/patch_analog.c b/sound/pci/hda/patch_analog.c index 447eda1..1a36137 100644 --- a/sound/pci/hda/patch_analog.c +++ b/sound/pci/hda/patch_analog.c @@ -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; -- 1.8.2.3