Hello!
Quoting Takashi Iwai tiwai@suse.de:
At Sun, 31 Jul 2011 23:39:45 -0400, Pavel Roskin wrote:
My laptop has ALC269, bit it also used the DMIC quirk: SND_PCI_QUIRK(0x1043, 0x83ce, "ASUS P1005HA", ALC269_DMIC),
It might be that ALC269 has a same or similar COEF like ALC271 or ALC889. For ALC271, the following verbs do the mono-mixing of d-mic,
{0x20, AC_VERB_SET_COEF_INDEX, 0x0d}, {0x20, AC_VERB_SET_PROC_COEF, 0x4000},
while for ALC889, the following do:
{0x20, AC_VERB_SET_COEF_INDEX, 0x0b}, {0x20, AC_VERB_SET_PROC_COEF, 0x0003},
Try the above via hda-verb once whether it has any effect on your machine.
I tried both using hda-verb 0.3 but didn't have any effect. I tied playing with hda-verb a little bit. For COEF_INDEX 0xb, the initial value returned by GET_PROC_COEF is 0x5cc0. The lowest value (after writing 0) is 0x5c00. The highest value (after writing 0xffff) is 0x5dff. Writing 0x0003 results in 0x5c03, quite predictably.
For COEF_INDEX 0xd, the initial value is 0xf000. The range is from 0 to 0xffc0. Setting 0x4000 succeeds, 0x4000 is read back.
Maybe I could run some script looking for acoustic feedback?
This gives feedback:
arecord -f cd --channels 2 | aplay -
This gives no feedback (pulse audio is used, output volume is maximal):
arecord -f cd --channels 1 | aplay -