Messages in this thread | | | Date | Thu, 14 Aug 2008 20:10:03 +0100 | From | "Daniel J Blueman" <> | Subject | Re: ALC883 recording troubles... |
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Hi Takashi,
I am still finding this recording +ve saturation on my ALC883 Intel HDA sound device with 2.6.27-rc3 (ie ALSA 1.0.17 drivers) and ALSA 1.0.16-1 libraries on Ubuntu Intrepid.
The previous workaround still 'gets us out of jail':
# ./hda-verb /dev/snd/hwC0D0 0x23 SET_AMP_GAIN_MUTE 0x7180 nid = 0x23, verb = 0x300, param = 0x7180 value = 0x0
Note, we see this message "hda_codec: Unknown model for ALC883, trying auto-probe from BIOS..." as before on this Asus P5E-VM HDMI motherboard with current BIOS.
How can we improve the situation, as out the box, the front/rear mic inputs are (still) useless?
Many thanks, Daniel
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: >> 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. -- Daniel J Blueman
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