[alsa-devel] pci/hda/patch_via.c - broken between 2.6.36 and 2.6.37 (bisected)

[Mark Goldstein]

Hi,

On Sun, Feb 20, 2011 at 12:50 PM, Wolfgang Scheicher
<wolfgang.scheicher at gmail.com> wrote:
>
> After the mentioned Kernel upgrade quite a view things went wrong on my
> hardware ( http://www.asrock.com/mb/overview.asp?Model=890GM%20Pro3 ):
>
> * Microphone doesn't work anymore. neither the front mic nor the rear one.
> Tried all thinkable settings.
>
> * Increasing Microphone levels leads to some strange internal feedback. That
> means, at some point when the feedback starts, it just starts, but i have no
> clue what audio source did actually trigger it.
>
> * Touching the mixer channel "Smart 5.1" in alsamixer makes alsamicer crash.
>
>
> After quite some days of frustration and the inability to get help i however
> managed to learn how to build a kernel and how to git bisect. So this is
> what i did:
>
>
> root at Blackrock ~src/alsa-kernel (git)-[7b315bb...|bisect] # git bisect log
> git bisect start '--' 'sound/pci'
> # bad: [81a2f603f94d6da108ddd8e3535294445097f730] ALSA: ac97: replace open-
> coded, error-prone stuff with AC97 bit defines
> git bisect bad 81a2f603f94d6da108ddd8e3535294445097f730
> # good: [f6f94e2ab1b33f0082ac22d71f66385a60d8157f] Linux 2.6.36
> git bisect good f6f94e2ab1b33f0082ac22d71f66385a60d8157f
> # bad: [28c4edb71d21623f1e47422194d865d2b6712fd4] ALSA: HDA: Rename "Int
> Mic" to "Internal Mic"
> git bisect bad 28c4edb71d21623f1e47422194d865d2b6712fd4
> # bad: [0e7adbe263f89ea2ef15b5af5e80a812b2a85025] ALSA: hda - Disable sticky
> PCM stream assignment for AD codecs
> git bisect bad 0e7adbe263f89ea2ef15b5af5e80a812b2a85025
> # bad: [5637edb2e1c2d13b276748508ae17f319fb7f066] ALSA: HDA: Sort CXT5066
> quirk table
> git bisect bad 5637edb2e1c2d13b276748508ae17f319fb7f066
> # bad: [18675e4283f575594d55ef1239c14ab5b4de53b6] ALSA: hda - Add fixup for
> FSC Celsius H270
> git bisect bad 18675e4283f575594d55ef1239c14ab5b4de53b6
> # good: [eea7dc932bfa802ad0377755ea821f416f4f8623] ALSA: hda - Use new
> inputs[] field to parse input-pins for STAC/IDT codecs
> git bisect good eea7dc932bfa802ad0377755ea821f416f4f8623
> # bad: [263d0328c46995d8e4fb478005177839104483d2] ALSA: hda - Improve input
> control names for IDT/STAC codecs
> git bisect bad 263d0328c46995d8e4fb478005177839104483d2
> # bad: [9737731d64bfa64ab4fc04b46ae5b650f6432222] Merge branch 'fix/hda'
> into topic/hda
> git bisect bad 9737731d64bfa64ab4fc04b46ae5b650f6432222
> # bad: [7b315bb4980448250c80a7464c256b54d546cb26] ALSA: hda - Use new
> inputs[] field to parse input-pins for VIA codecs
> git bisect bad 7b315bb4980448250c80a7464c256b54d546cb26
>
>
> root at Blackrock ~src/alsa-kernel (git)-[7b315bb...|bisect] # git bisect bad
> 7b315bb4980448250c80a7464c256b54d546cb26 is the first bad commit
> commit 7b315bb4980448250c80a7464c256b54d546cb26
> Author: Takashi Iwai <tiwai at suse.de>
> Date:   Mon Aug 30 13:06:30 2010 +0200
>
>    ALSA: hda - Use new inputs[] field to parse input-pins for VIA codecs
>
>    Signed-off-by: Takashi Iwai <tiwai at suse.de>
>
> :040000 040000 fb32bef12d78f90f00020cf375fddd36be1cdfbe
> 02f61291093ce6c7c8e7e1bd98fd87f9338702a1 M      sound
>
>
>
> Oh, and here are debug infos from when i first tried to report the problem:
> bad:
> http://www.alsa-project.org/db/?f=0f29e6de98ea9fefae5c6e2adb43ff8f8eede697
>
> good:
> http://www.alsa-project.org/db/?f=11290fe50066e9bcd6a244f2c83b1c66c9dd201b
>
>
> I hope someone can take it from here. I'm not much more than a user. Just
> because i managed to build a kernel doesn't mean i can fix this bug.
>

I think the Mic part might be the same problem I had. I found out that
the following code:

static void via_auto_init_analog_input(struct hda_codec *codec)
{
       struct via_spec *spec = codec->spec;
       const struct auto_pin_cfg *cfg = &spec->autocfg;
       unsigned int ctl;
       int i;

       for (i = 0; i < cfg->num_inputs; i++) {
               hda_nid_t nid = cfg->inputs[i].pin;
               if (spec->smart51_enabled && is_smart51_pins(spec, nid))
                       ctl = PIN_OUT;
               else if (i == AUTO_PIN_MIC)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^
                       ctl = PIN_VREF50;
               else
                       ctl = PIN_IN;
               snd_hda_codec_write(codec, nid, 0,
                                   AC_VERB_SET_PIN_WIDGET_CONTROL, ctl);
       }
}

configures correctly only the first MIC (in my case it was Rear MIC).
Front Mic pin was configured as HiZ.
Changing the underlined condition to

else if (cfg->input[i].type == AUTO_PIN_MIC)

resolved the issue for me. (In alsa driver 1.0.23 this code was
different, it checked that i <= FRONT_MIC index).

I'm also just the user of alsa driver, so can't decide whether this is
the proper fix. Maybe someone of knowledgeable developers could check
it.

-- 
Mark Goldstein