bug: reconfig broken on kernel 4.5

bug: reconfig broken on kernel 4.5

[Jochen Henneberg]

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.

Regards,
Jochen

Re: bug: reconfig broken on kernel 4.5

[Takashi Iwai]

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.


thanks,

Takashi

Re: bug: reconfig broken on kernel 4.5

[Takashi Iwai]

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.


Takashi

-- 8< --
From: Takashi Iwai <tiwai@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@henneberg-systemdesign.com>
Cc: <stable@vger.kernel.org> # v4.1+
Signed-off-by: Takashi Iwai <tiwai@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);
-- 
2.8.2

Re: 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@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@henneberg-systemdesign.com>
> Cc: <stable@vger.kernel.org> # v4.1+
> Signed-off-by: Takashi Iwai <tiwai@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);

-- 
Henneberg - Systemdesign
Jochen Henneberg
Loehnfeld 26
21423 Winsen (Luhe)
--
Fon: +49 4174 668 773
Mobile: +49 172 160 14 69
Fax: +49 321 210 761 64
www: www.henneberg-systemdesign.com

Re: bug: reconfig broken on kernel 4.5

[Takashi Iwai]

On Tue, 10 May 2016 11:47:56 +0200,
Jochen Henneberg wrote:
> 
> 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.

The patch has been merged now.


thanks,

Takashi