Hello,
A few days ago, I posted a patch to the linux kernel list, but afterwards I realised that it is more appropriate for the alsa list. So I repost it here.
Below is my patch for an issue on Dell E6500 notebooks with the Sigmatel stac92hd71b7 codec. In the default snd-hda-intel configuration, the sound going to the headphone jack goes comes directly from the DAC, resulting in very low volume output. The patch changes the codec's widget connections so that the internal mixer is put in between and sets its input amplifiers to the maximum value. The output to the internal speaker port has been left untouched. I have tested this and it gives a much better output.
Klaas De Craemer
diff -uNr linux-2.6.26.5/sound/pci/hda/patch_sigmatel.c linux-2.6.26.5.new/sound/pci/hda/patch_sigmatel.c --- linux-2.6.26.5/sound/pci/hda/patch_sigmatel.c 2008-09-08 19:40:20.000000000 +0200 +++ linux-2.6.26.5.new/sound/pci/hda/patch_sigmatel.c 2008-10-02 20:08:51.000000000 +0200 @@ -624,6 +624,22 @@ {} };
+static struct hda_verb stac92hd71b7_core_init[] = { + /* set master volume and direct control */ + { 0x28, AC_VERB_SET_VOLUME_KNOB_CONTROL, 0xff}, + /* connect headphone jack to mixer */ + { 0x0a, AC_VERB_SET_CONNECT_SEL, 0x02}, + /* unmute right and left channels for nodes 0x0a, 0xd, 0x0f */ + { 0x0a, AC_VERB_SET_AMP_GAIN_MUTE, AMP_IN_UNMUTE(0)}, + { 0x0d, AC_VERB_SET_AMP_GAIN_MUTE, AMP_IN_UNMUTE(0)}, + { 0x0f, AC_VERB_SET_AMP_GAIN_MUTE, AMP_IN_UNMUTE(0)}, + + /* Increase mixer volume for the two dac's */ + { 0x17, 0x370, 0x7f }, + { 0x17, 0x371, 0x7f }, + {} +}; + static struct hda_verb stac92hd71bxx_core_init[] = { /* set master volume and direct control */ { 0x28, AC_VERB_SET_VOLUME_KNOB_CONTROL, 0xff}, @@ -3642,6 +3658,10 @@ spec->mixer = stac92hd71bxx_mixer; spec->init = stac92hd71bxx_core_init; break; + case 0x111d76b2: /* Dell E6500 stac92hd71b7 configuration */ + spec->mixer = stac92hd71bxx_mixer; + spec->init = stac92hd71b7_core_init; + break; default: spec->mixer = stac92hd71bxx_analog_mixer; spec->init = stac92hd71bxx_analog_core_init;