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SubjectRe: [BISECTED] snd-hda-intel audio distortion in Linus' current tree
[Cc:; also, please cc: me explicitly as
well, since I'm not subscribed to either list]

On Wed, Sep 26, 2012 at 12:29 AM, Steven Noonan <> wrote:
> Started having audio problems when trying out the latest tree
> (v3.6-rc7-10-g56d27ad). When playing any kind of audio, there was
> significant distortion, mostly crackling noise. I'm using a Lenovo
> ThinkPad X230 (Panther Point).
> I did a git-bisect to locate the problem, and it seems this commit is to
> blame:
> c20c5a841cbe47f5b7812b57bd25397497e5fbc0 is the first bad commit
> commit c20c5a841cbe47f5b7812b57bd25397497e5fbc0
> Author: Seth Heasley <>
> Date: Thu Jun 14 14:23:53 2012 -0700
> ALSA: hda_intel: activate COMBO mode for Intel client chipsets
> This patch activates the COMBO position_fix for recent Intel client chipsets.
> COMBO mode is the recommended setting for Intel chipsets and eliminates HD
> audio warnings in dmesg. This patch has been tested on Lynx Point, Panther
> Point, and Cougar Pont.
> Signed-off-by: Seth Heasley <>
> Signed-off-by: Takashi Iwai <>
> It's pretty clear-cut. If I revert this patch, my sound starts
> functioning normally again.
> Any thoughts on how to proceed here? Can someone revert this, or is
> there some testing that I can do?
> Here's a pretty-printed bisection log, if needed:
> # good: [28a33cbc] Linux 3.5
> # bad: [b13bc8dd] Merge tag 'staging-3.6-rc1' of git://git.kernel.or
> # good: [3c4cfade] Merge git://
> # bad: [9fc37779] Merge tag 'usb-3.6-rc1' of git://
> # bad: [f14121ab] Merge tag 'dt-for-3.6' of git://
> # good: [d14b7a41] Merge branch 'for-linus' of git://
> # good: [15d47763] Merge branch 'for-3.5' into for-3.6
> # bad: [dbf7b591] Merge tag 'sound-3.6' of git://
> # bad: [1c76684d] ALSA: hda - add Haswell HDMI codec id
> # bad: [8b8d654b] ALSA: hda - Move one-time init codes from generic_
> # good: [80c8bfbe] ALSA: HDA: Create phantom jacks for fixed inputs a
> # bad: [ceaa86ba] ALSA: hda - Remove invalid init verbs for Nvidia 2
> # bad: [4b6ace9e] ALSA: hda - Add the support for VIA HDMI pin detec
> # bad: [c20c5a84] ALSA: hda_intel: activate COMBO mode for Intel cli
> - Steven
> --
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I can confirm that I've also hit this bug as well, and that it's still
present in stable 3.6.0. Strangely enough however, this only seems to
affect VLC for me; while playing audio through mplayer or any
gstreamer-based players (Rhythmbox, Totem, etc.), I don't encounter
any audio distortion. Possibly also related to [1]?

A workaround (other than reverting this commit) is to not use COMBO
mode, i.e. load snd-hda-intel with position_fix=2.

Please let me know if any more information is needed.

$ lspci -vvnn | grep -A8 Audio
00:1b.0 Audio device [0403]: Intel Corporation 7 Series/C210 Series
Chipset Family High Definition Audio Controller [8086:1e20] (rev 04)
Subsystem: Toshiba America Info Systems Device [1179:fb30]
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B- DisINTx+
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
<TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 0, Cache Line Size: 64 bytes
Interrupt: pin A routed to IRQ 46
Region 0: Memory at f7310000 (64-bit, non-prefetchable) [size=16K]
Capabilities: <access denied>
Kernel driver in use: snd_hda_intel

Machine: Toshiba Satellite P850
Distro: Debian wheezy/sid
ALSA 1.0.25; PulseAudio 2.0



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