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    SubjectRe: ALC883 recording troubles...
    On Sat, Jun 28, 2008 at 11:29 AM, Daniel J Blueman
    <> wrote:
    > On Sat, Jun 28, 2008 at 11:11 AM, Vegard Nossum <> wrote:
    >> (removed linux-kernel from Cc)
    >> On Sat, Jun 28, 2008 at 2:05 AM, Daniel J Blueman
    >> <> 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
    >>> # ./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 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?

    Daniel J Blueman

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