Messages in this thread | | | Date | Sat, 28 Jun 2008 13:29:32 +0100 | From | "Daniel J Blueman" <> | Subject | Re: ALC883 recording troubles... |
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On Sat, Jun 28, 2008 at 11:29 AM, Daniel J Blueman <daniel.blueman@gmail.com> wrote: > On Sat, Jun 28, 2008 at 11:11 AM, Vegard Nossum <vegard.nossum@gmail.com> wrote: >> (removed linux-kernel from Cc) >> >> On Sat, Jun 28, 2008 at 2:05 AM, Daniel J Blueman >> <daniel.blueman@gmail.com> wrote: >>> As the mic is working fine, but with this variable DC offset, it felt >>> like something needed tweaking in the mixer (summation) node. I >>> understand more about the node connectivity now, and found muting the >>> front mic mixer input and setting LR gain to 0 at mixer node 23h >>> addresses the issue: >>> >>> (from page 42 at ftp://66.104.77.130/pc/audio/ALC883_DataSheet_1.3.pdf) >>> >>> # ./hda-verb /dev/snd/hwC0D0 0x23 SET_AMP_GAIN_MUTE 0x7180 >> >> Are you saying that this fixes the problem completely for you? > > Yes, this addresses the problem squarely. The front mix mixer input is > adding this offset, looks like they have a capacitor between a > reference voltage and the pin or something, so it floats up. > >>> Vegard - your HD bus enumeration looks similar and I'd bet the vendor >>> followed the same Realtek application note, so can you give this a >>> shot too? If not, try mixer node 20h. >> >> I agree. Thanks for the link, I found ALC268 now as well, and I am >> experimenting... >> >> I think 23h is [in]correct -- this is the one with caps f00040h for me too. >> >> But neither of them had any effect at all. > > OK, I'll take another look at the debug output you posted; I forgot > you aren't using the ALC883.
Using your dumped config and ftp://202.65.194.211/pc/audio/ALC268_DataSheet_1.3.pdf page 42, your front mic pin complex is at node 19h; the mixers connecting to it are at nodes 0Bh, 22h and 23h, all at the second input index, so one of these should work:
# ./hda-verb /dev/snd/hwC0D0 0x0b SET_AMP_GAIN_MUTE 0x7280 # ./hda-verb /dev/snd/hwC0D0 0x22 SET_AMP_GAIN_MUTE 0x7280 # ./hda-verb /dev/snd/hwC0D0 0x23 SET_AMP_GAIN_MUTE 0x7280
On my ALC883, we need to mute the first input instead, thus 0x7180. Can you see if the above helps you out?
Thanks, Daniel -- Daniel J Blueman
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