[alsa-devel] bug: reconfig broken on kernel 4.5

[Jochen Henneberg]

On Di, 2016-05-10 at 10:36 +0200, Takashi Iwai wrote:
> On Mon, 09 May 2016 16:11:46 +0200,
> Takashi Iwai wrote:
> > 
> > On Mon, 09 May 2016 10:22:49 +0200,
> > Jochen Henneberg wrote:
> > > 
> > > Hi,
> > > 
> > > it looks as if 'reconfig' feature is broken since the sysfs attributes
> > > have been moved to device attributes. In hda_sysfs.c:reconfig_codec()
> > > the device is cleared with snd_hda_codec_reset() which calls
> > > snd_hdac_device_unregister() which removes the sysfs entries (including
> > > the currently in-use 'reconfig'), the re-registration fails afterwards
> > > in snd_hda_codec_build_controls().
> > > I am not sure when things got broken, but snd_hda_codec_reset()
> > > called from reconfig_codec() unregisters the device and removes the
> > > sysfs entries where in the past it only stripped all configurations
> > > (pcms, controls ...) from the device.
> > 
> > Hrm, OK, something got broken indeed there.  I'll check it later.
> 
> Actually it's not about the sysfs, but rather the superfluous calls of
> snd_hda_codec_build_controls() & co.  The fix patch is below.
> 

Sorry for the confusion, I did not notice. Anyway, I have tested the
patch with 4.5, changed codec hints, reconfig and no error messages and
the changed hints have been respected after reconfig, looks good for me.

Jochen

> 
> Takashi
> 
> -- 8< --
> From: Takashi Iwai <tiwai at suse.de>
> Subject: [PATCH] ALSA: hda - Fix broken reconfig
> 
> The HD-audio reconfig function got broken in the recent kernels,
> typically resulting in a failure like:
>   snd_hda_intel 0000:00:1b.0: control 3:0:0:Playback Channel Map:0 is already present
> 
> This is because of the code restructuring to move the PCM and control
> instantiation into the codec drive probe, by the commit [bcd96557bd0a:
> ALSA: hda - Build PCMs and controls at codec driver probe].  Although
> the commit above removed the calls of snd_hda_codec_build_pcms() and
> *_build_controls() at the controller driver probe, the similar calls
> in the reconfig were still left forgotten.  This caused the
> conflicting and duplicated PCMs and controls.
> 
> The fix is trivial: just remove these superfluous calls from
> reconfig_codec().
> 
> Fixes: bcd96557bd0a ('ALSA: hda - Build PCMs and controls at codec driver probe')
> Reported-by: Jochen Henneberg <jh at henneberg-systemdesign.com>
> Cc: <stable at vger.kernel.org> # v4.1+
> Signed-off-by: Takashi Iwai <tiwai at suse.de>
> ---
>  sound/pci/hda/hda_sysfs.c | 8 --------
>  1 file changed, 8 deletions(-)
> 
> diff --git a/sound/pci/hda/hda_sysfs.c b/sound/pci/hda/hda_sysfs.c
> index 64e0d1d81ca5..9739fce9e032 100644
> --- a/sound/pci/hda/hda_sysfs.c
> +++ b/sound/pci/hda/hda_sysfs.c
> @@ -141,14 +141,6 @@ static int reconfig_codec(struct hda_codec *codec)
>  	err = snd_hda_codec_configure(codec);
>  	if (err < 0)
>  		goto error;
> -	/* rebuild PCMs */
> -	err = snd_hda_codec_build_pcms(codec);
> -	if (err < 0)
> -		goto error;
> -	/* rebuild mixers */
> -	err = snd_hda_codec_build_controls(codec);
> -	if (err < 0)
> -		goto error;
>  	err = snd_card_register(codec->card);
>   error:
>  	snd_hda_power_down(codec);

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