Problems with the DP MST audio support patchset

Problems with the DP MST audio support patchset

[Pascal Wichmann]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Hello,

I am not sure whether alsa-devel is the right place for this kind of
question. If it is not, please tell me a better place for them.

I am building my kernel against the drm-tip freedesktop repository which
includes the patches from December 2016 (message id
<1480992519-108079-1-git-send-email-libin.yang@intel.com> and
follow-ups on alsa-devel). I am using a ThinkPad X250 and the ThinkPad
Ultra
Dock with the HDMI output connected to my YAMAHA HTR-2866; this hdmi
output is seen as display port and uses DP MST from the dock.

In principle, everything is working quite well; however, I frequently
recognize two weird behaviours:

* First of all, my audio receiver has 5.1 support. When I
  configure my laptop to send 5.1 audio using alsa or pulseaudio, there
is
  only silence and no audio signal reaches the receiver; however, when I
  choose 7.1 digital surround (which my receiver actually does not suppo
rt
  natively), everything works well and the two additional speakers are
split
  to the existing ones (I do not know whether alsa/the kernel or the
  receiver
  does this, probably it is the receiver).
  This problem is pretty much only esthetical, as everything works fine
  if I use the 7.1 "work-around" (Digital Stereo does work also,
  but obviously does not support the full 5.1 setup)
* The other problem -- which is actually very annoying -- is that there
  frequently is silence though there is audio playing; this happens now
  and then, but when there has been *no* output for a while, it always
  happens a few seconds after starting the new output and lasts for two
  to three seconds.
  During these periods of silence, the icons on my receiver indicating
  that there is an audio source are also gone.
  This problem occurs with 7.1 configuration as well as with Digital
  Stereo.

I am not sure what these problems are caused by and do not know what kin
d
of debug information you may require to get more hints on how to solve
them. Any hints are appreciated.

Thank you for your advice,
Pascal Wichmann
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Re: Problems with the DP MST audio support patchset

[Pascal Wichmann]

[-- Attachment #1.1.1: Type: text/plain, Size: 317 bytes --]

> I am not sure what these problems are caused by and do not know what kin
> d
> of debug information you may require to get more hints on how to solve
> them. Any hints are appreciated.

I have run alsa-info.sh to get more details:
http://www.alsa-project.org/db/?f=124149d1cae74a6622176e13f9c5c63b5411af88


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Re: Problems with the DP MST audio support patchset

[Yang, Libin]

Hi Wichmann,

Do you mean the issue is caused by the patches 1480992519-108079-1-git-send-email-libin.yang@intel.com?

I can't see which patches are included you mentioned in the link.

Do you know if the DP MST audio mode is used in your case?

Regards,
Libin


>-----Original Message-----
>From: alsa-devel-bounces@alsa-project.org [mailto:alsa-devel-bounces@alsa-
>project.org] On Behalf Of Pascal Wichmann
>Sent: Thursday, March 30, 2017 6:22 PM
>To: Libin Yang <libin.yang@linux.intel.com>; alsa-devel@alsa-project.org
>Subject: Re: [alsa-devel] Problems with the DP MST audio support patchset
>
>> I am not sure what these problems are caused by and do not know what
>> kin d of debug information you may require to get more hints on how to
>> solve them. Any hints are appreciated.
>
>I have run alsa-info.sh to get more details:
>http://www.alsa-
>project.org/db/?f=124149d1cae74a6622176e13f9c5c63b5411af88

Re: Problems with the DP MST audio support patchset

[Pascal Wichmann]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Hi,

> Do you mean the issue is caused by the patches 
> 1480992519-108079-1-git-send-email-libin.yang@intel.com?
I don't know whether the issues are caused directly by the
specific patches; without them, digital audio does not work at
all in my setup. Using analog audio however does not have the problems
mentioned in my first email.

> I can't see which patches are included you mentioned in the link.
I am building my kernel from drm-tip. The relevant patches enabling DP M
ST
audio seem to be "ALSA: hda - add DP mst verb support" [0] as well as
"ALSA: hda - add DP MST audio support" [1].

> Do you know if the DP MST audio mode is used in your case?
I think it is used; at least dp/hdmi audio does not work at all without
building against drm-tip. (the outputs are all stated as unplugged
and unavailable in pavucontrol for example)
Is there any way to know for sure?

Regards,
Pascal

[0]
https://cgit.freedesktop.org/drm-tip/commit/?id=13800f397ee3b4996f316b9c
aa8482cb90edef0d
[1]
https://cgit.freedesktop.org/drm-tip/commit/?id=9152085defb6426ce8f9989c
a27e4450daefbd89
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Re: Problems with the DP MST audio support patchset

[Yang, Libin]

Hi Pascal,

>-----Original Message-----
>From: Pascal Wichmann [mailto:pascal.wichmann@pa-w.de]
>Sent: Friday, March 31, 2017 12:36 AM
>To: Yang, Libin <libin.yang@intel.com>; Libin Yang
><libin.yang@linux.intel.com>; alsa-devel@alsa-project.org
>Subject: Re: [alsa-devel] Problems with the DP MST audio support patchset
>
>-----BEGIN PGP SIGNED MESSAGE-----
>Hash: SHA256
>
>Hi,
>
>> Do you mean the issue is caused by the patches
>> 1480992519-108079-1-git-send-email-libin.yang@intel.com?
>I don't know whether the issues are caused directly by the specific patches;
>without them, digital audio does not work at all in my setup. Using analog
>audio however does not have the problems mentioned in my first email.
>
>> I can't see which patches are included you mentioned in the link.
>I am building my kernel from drm-tip. The relevant patches enabling DP M ST
>audio seem to be "ALSA: hda - add DP mst verb support" [0] as well as
>"ALSA: hda - add DP MST audio support" [1].
>
>> Do you know if the DP MST audio mode is used in your case?
>I think it is used; at least dp/hdmi audio does not work at all without building
>against drm-tip. (the outputs are all stated as unplugged and unavailable in
>pavucontrol for example) Is there any way to know for sure?

Get it. Basically, 5.1 audio should work. What format are you using for
testing the 5.1 audio?

Regards,
Libin

>
>Regards,
>Pascal
>
>[0]
>https://cgit.freedesktop.org/drm-tip/commit/?id=13800f397ee3b4996f316b9c
>aa8482cb90edef0d
>[1]
>https://cgit.freedesktop.org/drm-tip/commit/?id=9152085defb6426ce8f9989c
>a27e4450daefbd89
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Re: Problems with the DP MST audio support patchset

[Pascal Wichmann]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Hi,

> Get it. Basically, 5.1 audio should work. What format are you using
>  for testing the 5.1 audio?
I do not use a specific format for testing; the issue occurs using
speaker-test as well as using any application with audio output as for
example vlc, rhythmbox or a browser like chromium or firefox.

As mentioned, when configuring the output as digital stereo or 7.1
surround, except for the second issue explained in my first mail
(which actually is more annoying) the audio works.

Regards,
Pascal
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Re: Problems with the DP MST audio support patchset

[Yang, Libin]

Hi Takashi,

Do you have some suggestion for this issue.

Hi Pascal,

Please see my comments below.

>-----Original Message-----
>From: Pascal Wichmann [mailto:pascal.wichmann@pa-w.de]
>Sent: Friday, March 31, 2017 2:12 PM
>To: Yang, Libin <libin.yang@intel.com>; Libin Yang
><libin.yang@linux.intel.com>; alsa-devel@alsa-project.org
>Subject: Re: [alsa-devel] Problems with the DP MST audio support patchset
>
>-----BEGIN PGP SIGNED MESSAGE-----
>Hash: SHA256
>
>Hi,
>
>> Get it. Basically, 5.1 audio should work. What format are you using
>> for testing the 5.1 audio?
>I do not use a specific format for testing; the issue occurs using speaker-test as
>well as using any application with audio output as for example vlc, rhythmbox
>or a browser like chromium or firefox.
>
>As mentioned, when configuring the output as digital stereo or 7.1 surround,
>except for the second issue explained in my first mail (which actually is more
>annoying) the audio works.

Yes, that's strange. I asked about the format is try to make sure you are using the
same format as 7.1. As you are using speaker-test, the format is not the problem.

We tried to reproduce this issue here and unfortunately failed. We can't make
the HDMI work through our AV receiver. 

I checked your alsa-info.sh output and didn't find the problem.

Regard,
Libin

>
>Regards,
>Pascal
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Re: Problems with the DP MST audio support patchset

[Takashi Iwai]

On Fri, 31 Mar 2017 08:29:01 +0200,
Yang, Libin wrote:
> 
> Hi Takashi,
> 
> Do you have some suggestion for this issue.

I guess the digital-7.1 corresponds to HBR, and it's a special setup.
Meanwhile 5.1 output he has tried is likely the LPCM, so both are in a
completely differently manner.


Takashi

> 
> Hi Pascal,
> 
> Please see my comments below.
> 
> >-----Original Message-----
> >From: Pascal Wichmann [mailto:pascal.wichmann@pa-w.de]
> >Sent: Friday, March 31, 2017 2:12 PM
> >To: Yang, Libin <libin.yang@intel.com>; Libin Yang
> ><libin.yang@linux.intel.com>; alsa-devel@alsa-project.org
> >Subject: Re: [alsa-devel] Problems with the DP MST audio support patchset
> >
> >-----BEGIN PGP SIGNED MESSAGE-----
> >Hash: SHA256
> >
> >Hi,
> >
> >> Get it. Basically, 5.1 audio should work. What format are you using
> >> for testing the 5.1 audio?
> >I do not use a specific format for testing; the issue occurs using speaker-test as
> >well as using any application with audio output as for example vlc, rhythmbox
> >or a browser like chromium or firefox.
> >
> >As mentioned, when configuring the output as digital stereo or 7.1 surround,
> >except for the second issue explained in my first mail (which actually is more
> >annoying) the audio works.
> 
> Yes, that's strange. I asked about the format is try to make sure you are using the
> same format as 7.1. As you are using speaker-test, the format is not the problem.
> 
> We tried to reproduce this issue here and unfortunately failed. We can't make
> the HDMI work through our AV receiver. 
> 
> I checked your alsa-info.sh output and didn't find the problem.
> 
> Regard,
> Libin
> 
> >
> >Regards,
> >Pascal
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Re: Problems with the DP MST audio support patchset

[Pascal Wichmann]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Hi all,

> I guess the digital-7.1 corresponds to HBR, and it's a special 
> setup. Meanwhile 5.1 output he has tried is likely the LPCM, so
> both are in a completely differently manner.
Thank you, that sounds like a good explanation for my first issue.


For the other problem, that seems to be some kind of HDMI handshake
related issue to me.
I have done some more research and found similar
problems like [0]. Their solution to enable a pulseaudio loopback seemed
to improve the situation at first; at least during the last two hours,
the problem did not occur as often as it did before (without explicitly
provoking it), but it occurred though.

In addition, I have disabled the power save options of the snd_hda_intel
module:
> options snd_hda_intel power_save=0 power_save_controller=N
This however does not seem to have any impact on the problem at all.

I have also found a way to reliably reproduce the problem by muting and
immediately unmuting the output in alsamixer having some audio running
- -- this way, the output gets silenced for a few seconds a moment after
the unmuting almost always.

Is the above solution using the pulseaudio loopback module not enough to
prevent handshake issues? Do handshake issues sound suitable at all? Do
you have any other ideas where the problem may lies?


Regards,
Pascal

[0]
https://ubuntuforums.org/showthread.php?t=2215224&p=13117108#post1311710
8
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HuO9NFzKlDKGYE82LSFrqNrngJVxvpVK8tC4BegbTodzB00GFPcHaO6hJR1b40SK
gGbQXZ1yfhtQPOGPflcDJiXp4f2mCI9JpbTb+UMenk2qcSx9GU29HZ33XWg1xTL0
ecHtdlN0pXwEtxTG5yMijJZ4aadCOwHLoLN01OJXG4UIWO+By88=
=aohm
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Re: Problems with the DP MST audio support patchset

[Takashi Iwai]

On Fri, 31 Mar 2017 21:04:37 +0200,
Pascal Wichmann wrote:
> 
> Hi all,
> 
> > I guess the digital-7.1 corresponds to HBR, and it's a special 
> > setup. Meanwhile 5.1 output he has tried is likely the LPCM, so
> > both are in a completely differently manner.
> Thank you, that sounds like a good explanation for my first issue.
> 
> 
> For the other problem, that seems to be some kind of HDMI handshake
> related issue to me.
> I have done some more research and found similar
> problems like [0]. Their solution to enable a pulseaudio loopback seemed
> to improve the situation at first; at least during the last two hours,
> the problem did not occur as often as it did before (without explicitly
> provoking it), but it occurred though.
> 
> In addition, I have disabled the power save options of the snd_hda_intel
> module:
> > options snd_hda_intel power_save=0 power_save_controller=N
> This however does not seem to have any impact on the problem at all.
> 
> I have also found a way to reliably reproduce the problem by muting and
> immediately unmuting the output in alsamixer having some audio running
> - -- this way, the output gets silenced for a few seconds a moment after
> the unmuting almost always.
> 
> Is the above solution using the pulseaudio loopback module not enough to
> prevent handshake issues? Do handshake issues sound suitable at all? Do
> you have any other ideas where the problem may lies?

It's a general problem with many digital receivers.  When the stream
stops, a digital receiver turn itself off until it re-receives a new
stream.  And this on/off takes a few seconds.

Thus, you must not stop the stream, but you'd need to keep sending the
silent stream even if you stop a playback.


Takashi

Re: Problems with the DP MST audio support patchset

[Pascal Wichmann]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Hi Takashi,


> It's a general problem with many digital receivers.  When the 
> stream stops, a digital receiver turn itself off until it 
> re-receives a new stream.  And this on/off takes a few seconds.

> Thus, you must not stop the stream, but you'd need to keep sending
>  the silent stream even if you stop a playback.

Thank you for your explanation.

I have made sure that the following process is always running when
pulseaudio is:
> play -n -c1 synth sin gain -100 > /dev/null 2>&1 &
This way, there is always a stream that never stops. The problem of the
silent
second after starting new audio is solved by that. (I have made sure
that the correct output card is used.)

However, every few minutes, the stream still seems to be gone for half a
second; even during active additional audio playback (as well as the
above sox command), the audio output is silenced for a second and the
icons on my
receiver are gone meanwhile.
Though, pulseaudio does have an output stream all the time without any
pause. So there seems to be some other place where the outgoing DP MST
stream is lost, delayed or interrupted causing this issue.

During the last few hours, the period of this disruption has been quite
consistent between every 4 and 6 minutes.

Do you have any other ideas what might cause this or where parts of
the stream could get lost?


Regards,
Pascal

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Re: Problems with the DP MST audio support patchset

[Michael Forney]

On Thu, Mar 30, 2017 at 9:35 AM, Pascal Wichmann
<pascal.wichmann@pa-w.de> wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA256
>
> Hi,
>
>> Do you mean the issue is caused by the patches
>> 1480992519-108079-1-git-send-email-libin.yang@intel.com?
> I don't know whether the issues are caused directly by the
> specific patches; without them, digital audio does not work at
> all in my setup. Using analog audio however does not have the problems
> mentioned in my first email.
>
>> I can't see which patches are included you mentioned in the link.
> I am building my kernel from drm-tip. The relevant patches enabling DP M
> ST
> audio seem to be "ALSA: hda - add DP mst verb support" [0] as well as
> "ALSA: hda - add DP MST audio support" [1].

Hi,

I recently updated my kernel to 4.11, and am experiencing similar
problems as Pascal. I have a Skylake processor and DP output hooked up
with a DP to HDMI cable to an Onkyo SR-606 receiver.

I can't get audio to work at all through my receiver anymore. I tried
both DTS and PCM audio files. I bisected it to the above mentioned
commit 9152085defb6426ce8f9989ca27e4450daefbd89 (ALSA: hda - add DP
MST audio support).

>> Do you know if the DP MST audio mode is used in your case?

I don't know what DP MST is or how to tell if I'm using it. However, I
noticed that when it does work, `aplay -L` gives me

hdmi:CARD=PCH,DEV=0
    HDA Intel PCH, HDMI 0
    HDMI Audio Output
hdmi:CARD=PCH,DEV=1
    HDA Intel PCH, HDMI 1
    HDMI Audio Output

and when it doesn't, I get

hdmi:CARD=PCH,DEV=0
    HDA Intel PCH, Generic Digital
    HDMI Audio Output

> I think it is used; at least dp/hdmi audio does not work at all without
> building against drm-tip. (the outputs are all stated as unplugged
> and unavailable in pavucontrol for example)
> Is there any way to know for sure?

I tried building against drm-tip as well as v4.12-rc2, but observed
the same issue. I am not using pulseaudio, but alsa directly.

Any help would be appreciated.

Thanks,
Michael

Re: Problems with the DP MST audio support patchset

[Michael Forney]

On Thu, May 25, 2017 at 1:21 AM, Michael Forney <mforney@mforney.org> wrote:
> Hi,
>
> I recently updated my kernel to 4.11, and am experiencing similar
> problems as Pascal. I have a Skylake processor and DP output hooked up
> with a DP to HDMI cable to an Onkyo SR-606 receiver.
>
> I can't get audio to work at all through my receiver anymore. I tried
> both DTS and PCM audio files. I bisected it to the above mentioned
> commit 9152085defb6426ce8f9989ca27e4450daefbd89 (ALSA: hda - add DP
> MST audio support).
>
>>> Do you know if the DP MST audio mode is used in your case?
>
> I don't know what DP MST is or how to tell if I'm using it. However, I
> noticed that when it does work, `aplay -L` gives me
>
> hdmi:CARD=PCH,DEV=0
>     HDA Intel PCH, HDMI 0
>     HDMI Audio Output
> hdmi:CARD=PCH,DEV=1
>     HDA Intel PCH, HDMI 1
>     HDMI Audio Output
>
> and when it doesn't, I get
>
> hdmi:CARD=PCH,DEV=0
>     HDA Intel PCH, Generic Digital
>     HDMI Audio Output

Well, I noticed in my dmesg log for 4.11:

<4>[    1.201789] snd_hda_intel 0000:00:1f.3: Too many HDMI devices
<4>[    1.201790] snd_hda_intel 0000:00:1f.3: Consider building the
kernel with CONFIG_SND_DYNAMIC_MINORS=y
<4>[    1.201792] snd_hda_intel 0000:00:1f.3: Too many HDMI devices
<4>[    1.201794] snd_hda_intel 0000:00:1f.3: Consider building the
kernel with CONFIG_SND_DYNAMIC_MINORS=y
<4>[    1.201795] snd_hda_intel 0000:00:1f.3: Too many HDMI devices
<4>[    1.201797] snd_hda_intel 0000:00:1f.3: Consider building the
kernel with CONFIG_SND_DYNAMIC_MINORS=y
<3>[    1.202668] snd_hda_intel 0000:00:1f.3: control 3:0:0:ELD:0 is
already present
<4>[    1.202737] snd_hda_codec_hdmi: probe of hdaudioC0D2 failed with error -16
<4>[    1.204335] snd_hda_intel 0000:00:1f.3: Too many HDMI devices
<4>[    1.204337] snd_hda_intel 0000:00:1f.3: Consider building the
kernel with CONFIG_SND_DYNAMIC_MINORS=y
<4>[    1.204338] snd_hda_intel 0000:00:1f.3: Too many HDMI devices
<4>[    1.204340] snd_hda_intel 0000:00:1f.3: Consider building the
kernel with CONFIG_SND_DYNAMIC_MINORS=y
<4>[    1.204341] snd_hda_intel 0000:00:1f.3: Too many HDMI devices
<4>[    1.204343] snd_hda_intel 0000:00:1f.3: Consider building the
kernel with CONFIG_SND_DYNAMIC_MINORS=y
<3>[    1.205412] snd_hda_intel 0000:00:1f.3: control 3:0:0:ELD:0 is
already present
<4>[    1.205464] snd_hda_codec_hdmi: probe of hdaudioC0D2 failed with error -16
<6>[    1.205644] snd_hda_codec_generic hdaudioC0D2: ignore pin 0x7,
too many assigned pins
<6>[    1.205648] snd_hda_codec_generic hdaudioC0D2: autoconfig for
Generic: line_outs=0 (0x0/0x0/0x0/0x0/0x0) type:line
<6>[    1.205651] snd_hda_codec_generic hdaudioC0D2:    speaker_outs=0
(0x0/0x0/0x0/0x0/0x0)
<6>[    1.205653] snd_hda_codec_generic hdaudioC0D2:    hp_outs=0
(0x0/0x0/0x0/0x0/0x0)
<6>[    1.205655] snd_hda_codec_generic hdaudioC0D2:    mono: mono_out=0x0
<6>[    1.205656] snd_hda_codec_generic hdaudioC0D2:    dig-out=0x5/0x6
<6>[    1.205658] snd_hda_codec_generic hdaudioC0D2:    inputs:
<6>[    1.207882] input: HDA Intel PCH Mic as
/devices/pci0000:00/0000:00:1f.3/sound/card0/input4
<6>[    1.207979] input: HDA Intel PCH Front Headphone as
/devices/pci0000:00/0000:00:1f.3/sound/card0/input5
<6>[    1.208070] input: HDA Intel PCH HDMI/DP,pcm=3 as
/devices/pci0000:00/0000:00:1f.3/sound/card0/input6
<6>[    1.208158] input: HDA Intel PCH HDMI/DP,pcm=7 as
/devices/pci0000:00/0000:00:1f.3/sound/card0/input7
<6>[    1.208246] input: HDA Intel PCH HDMI/DP as
/devices/pci0000:00/0000:00:1f.3/sound/card0/input8
<6>[    1.208335] input: HDA Intel PCH HDMI/DP as
/devices/pci0000:00/0000:00:1f.3/sound/card0/input9
<6>[    1.208441] input: HDA Intel PCH HDMI as
/devices/pci0000:00/0000:00:1f.3/sound/card0/input12
<6>[    1.208582] input: HDA Intel PCH HDMI as
/devices/pci0000:00/0000:00:1f.3/sound/card0/input13
<4>[    1.208700] ------------[ cut here ]------------
<4>[    1.208708] WARNING: CPU: 0 PID: 43 at fs/proc/generic.c:346
proc_register+0xe9/0x110
<4>[    1.208709] proc_dir_entry 'card0/eld#2.0' already registered
<4>[    1.208710] Modules linked in:
<4>[    1.208715] CPU: 0 PID: 43 Comm: kworker/0:1 Not tainted 4.11.3+ #41
<4>[    1.208716] Hardware name: HP HP EliteDesk 800 G2 DM 35W/8055,
BIOS N21 Ver. 02.14 04/28/2016
<4>[    1.208721] Workqueue: events azx_probe_work
<4>[    1.208723] Call Trace:
<4>[    1.208729]  dump_stack+0x4d/0x66
<4>[    1.208733]  __warn+0xc6/0xe0
<4>[    1.208737]  warn_slowpath_fmt+0x46/0x50
<4>[    1.208742]  proc_register+0xe9/0x110
<4>[    1.208746]  proc_create_data+0x71/0xc0
<4>[    1.208750]  snd_info_register+0x66/0xd0
<4>[    1.208753]  snd_info_register_recursive+0x5b/0x70
<4>[    1.208756]  snd_info_register_recursive+0x46/0x70
<4>[    1.208759]  snd_info_card_register+0x25/0xa0
<4>[    1.208764]  snd_card_register+0x140/0x190
<4>[    1.208769]  ? device_attach+0xb/0x10
<4>[    1.208773]  ? snd_hda_codec_configure+0xb1/0x120
<4>[    1.208776]  azx_probe_work+0x47d/0x860
<4>[    1.208778]  ? azx_probe_work+0x47d/0x860
<4>[    1.208783]  process_one_work+0x1ec/0x480
<4>[    1.208787]  worker_thread+0x43/0x4d0
<4>[    1.208790]  kthread+0x104/0x140
<4>[    1.208794]  ? process_one_work+0x480/0x480
<4>[    1.208797]  ? kthread_create_on_node+0x40/0x40
<4>[    1.208802]  ret_from_fork+0x29/0x40
<4>[    1.208805] ---[ end trace 538d7309f1b9646f ]---

So I added CONFIG_SND_DYNAMIC_MINORS=y as suggested (previously it was
disabled based on the help text). That seemed to do the trick.
However, the `proc_dir_entry 'card0/eld#2.0' already registered`
warning seems like it could be a bug despite this.

I guess the problem was this new MST feature means that now I have 5
HDMI outputs showing up, which is too many.

Sorry for the noise.

Re: Problems with the DP MST audio support patchset

[Yang, Libin]

Hi Michael,

>-----Original Message-----
>From: Michael Forney [mailto:mforney@mforney.org]
>Sent: Friday, May 26, 2017 12:10 PM
>To: Yang, Libin <libin.yang@intel.com>
>Cc: Libin Yang <libin.yang@linux.intel.com>; alsa-devel@alsa-project.org;
>Pascal Wichmann <pascal.wichmann@pa-w.de>
>Subject: Re: [alsa-devel] Problems with the DP MST audio support patchset
>
>On Thu, May 25, 2017 at 1:21 AM, Michael Forney <mforney@mforney.org>
>wrote:
>> Hi,
>>
>> I recently updated my kernel to 4.11, and am experiencing similar
>> problems as Pascal. I have a Skylake processor and DP output hooked up
>> with a DP to HDMI cable to an Onkyo SR-606 receiver.
>>
>> I can't get audio to work at all through my receiver anymore. I tried
>> both DTS and PCM audio files. I bisected it to the above mentioned
>> commit 9152085defb6426ce8f9989ca27e4450daefbd89 (ALSA: hda - add DP
>> MST audio support).
>>
>>>> Do you know if the DP MST audio mode is used in your case?
>>
>> I don't know what DP MST is or how to tell if I'm using it. However, I
>> noticed that when it does work, `aplay -L` gives me
>>
>> hdmi:CARD=PCH,DEV=0
>>     HDA Intel PCH, HDMI 0
>>     HDMI Audio Output
>> hdmi:CARD=PCH,DEV=1
>>     HDA Intel PCH, HDMI 1
>>     HDMI Audio Output
>>
>> and when it doesn't, I get
>>
>> hdmi:CARD=PCH,DEV=0
>>     HDA Intel PCH, Generic Digital
>>     HDMI Audio Output
>
>Well, I noticed in my dmesg log for 4.11:
>
><4>[    1.201789] snd_hda_intel 0000:00:1f.3: Too many HDMI devices
><4>[    1.201790] snd_hda_intel 0000:00:1f.3: Consider building the
>kernel with CONFIG_SND_DYNAMIC_MINORS=y
><4>[    1.201792] snd_hda_intel 0000:00:1f.3: Too many HDMI devices
><4>[    1.201794] snd_hda_intel 0000:00:1f.3: Consider building the
>kernel with CONFIG_SND_DYNAMIC_MINORS=y
><4>[    1.201795] snd_hda_intel 0000:00:1f.3: Too many HDMI devices
><4>[    1.201797] snd_hda_intel 0000:00:1f.3: Consider building the
>kernel with CONFIG_SND_DYNAMIC_MINORS=y
><3>[    1.202668] snd_hda_intel 0000:00:1f.3: control 3:0:0:ELD:0 is
>already present
><4>[    1.202737] snd_hda_codec_hdmi: probe of hdaudioC0D2 failed with
>error -16
><4>[    1.204335] snd_hda_intel 0000:00:1f.3: Too many HDMI devices
><4>[    1.204337] snd_hda_intel 0000:00:1f.3: Consider building the
>kernel with CONFIG_SND_DYNAMIC_MINORS=y
><4>[    1.204338] snd_hda_intel 0000:00:1f.3: Too many HDMI devices
><4>[    1.204340] snd_hda_intel 0000:00:1f.3: Consider building the
>kernel with CONFIG_SND_DYNAMIC_MINORS=y
><4>[    1.204341] snd_hda_intel 0000:00:1f.3: Too many HDMI devices
><4>[    1.204343] snd_hda_intel 0000:00:1f.3: Consider building the
>kernel with CONFIG_SND_DYNAMIC_MINORS=y
><3>[    1.205412] snd_hda_intel 0000:00:1f.3: control 3:0:0:ELD:0 is
>already present
><4>[    1.205464] snd_hda_codec_hdmi: probe of hdaudioC0D2 failed with
>error -16
><6>[    1.205644] snd_hda_codec_generic hdaudioC0D2: ignore pin 0x7,
>too many assigned pins
><6>[    1.205648] snd_hda_codec_generic hdaudioC0D2: autoconfig for
>Generic: line_outs=0 (0x0/0x0/0x0/0x0/0x0) type:line
><6>[    1.205651] snd_hda_codec_generic hdaudioC0D2:    speaker_outs=0
>(0x0/0x0/0x0/0x0/0x0)
><6>[    1.205653] snd_hda_codec_generic hdaudioC0D2:    hp_outs=0
>(0x0/0x0/0x0/0x0/0x0)
><6>[    1.205655] snd_hda_codec_generic hdaudioC0D2:    mono:
>mono_out=0x0
><6>[    1.205656] snd_hda_codec_generic hdaudioC0D2:    dig-out=0x5/0x6
><6>[    1.205658] snd_hda_codec_generic hdaudioC0D2:    inputs:
><6>[    1.207882] input: HDA Intel PCH Mic as
>/devices/pci0000:00/0000:00:1f.3/sound/card0/input4
><6>[    1.207979] input: HDA Intel PCH Front Headphone as
>/devices/pci0000:00/0000:00:1f.3/sound/card0/input5
><6>[    1.208070] input: HDA Intel PCH HDMI/DP,pcm=3 as
>/devices/pci0000:00/0000:00:1f.3/sound/card0/input6
><6>[    1.208158] input: HDA Intel PCH HDMI/DP,pcm=7 as
>/devices/pci0000:00/0000:00:1f.3/sound/card0/input7
><6>[    1.208246] input: HDA Intel PCH HDMI/DP as
>/devices/pci0000:00/0000:00:1f.3/sound/card0/input8
><6>[    1.208335] input: HDA Intel PCH HDMI/DP as
>/devices/pci0000:00/0000:00:1f.3/sound/card0/input9
><6>[    1.208441] input: HDA Intel PCH HDMI as
>/devices/pci0000:00/0000:00:1f.3/sound/card0/input12
><6>[    1.208582] input: HDA Intel PCH HDMI as
>/devices/pci0000:00/0000:00:1f.3/sound/card0/input13
><4>[    1.208700] ------------[ cut here ]------------
><4>[    1.208708] WARNING: CPU: 0 PID: 43 at fs/proc/generic.c:346
>proc_register+0xe9/0x110
><4>[    1.208709] proc_dir_entry 'card0/eld#2.0' already registered
><4>[    1.208710] Modules linked in:
><4>[    1.208715] CPU: 0 PID: 43 Comm: kworker/0:1 Not tainted 4.11.3+ #41
><4>[    1.208716] Hardware name: HP HP EliteDesk 800 G2 DM 35W/8055,
>BIOS N21 Ver. 02.14 04/28/2016
><4>[    1.208721] Workqueue: events azx_probe_work
><4>[    1.208723] Call Trace:
><4>[    1.208729]  dump_stack+0x4d/0x66
><4>[    1.208733]  __warn+0xc6/0xe0
><4>[    1.208737]  warn_slowpath_fmt+0x46/0x50
><4>[    1.208742]  proc_register+0xe9/0x110
><4>[    1.208746]  proc_create_data+0x71/0xc0
><4>[    1.208750]  snd_info_register+0x66/0xd0
><4>[    1.208753]  snd_info_register_recursive+0x5b/0x70
><4>[    1.208756]  snd_info_register_recursive+0x46/0x70
><4>[    1.208759]  snd_info_card_register+0x25/0xa0
><4>[    1.208764]  snd_card_register+0x140/0x190
><4>[    1.208769]  ? device_attach+0xb/0x10
><4>[    1.208773]  ? snd_hda_codec_configure+0xb1/0x120
><4>[    1.208776]  azx_probe_work+0x47d/0x860
><4>[    1.208778]  ? azx_probe_work+0x47d/0x860
><4>[    1.208783]  process_one_work+0x1ec/0x480
><4>[    1.208787]  worker_thread+0x43/0x4d0
><4>[    1.208790]  kthread+0x104/0x140
><4>[    1.208794]  ? process_one_work+0x480/0x480
><4>[    1.208797]  ? kthread_create_on_node+0x40/0x40
><4>[    1.208802]  ret_from_fork+0x29/0x40
><4>[    1.208805] ---[ end trace 538d7309f1b9646f ]---
>
>So I added CONFIG_SND_DYNAMIC_MINORS=y as suggested (previously it was
>disabled based on the help text). That seemed to do the trick.

So the audio works well?

>However, the `proc_dir_entry 'card0/eld#2.0' already registered` warning
>seems like it could be a bug despite this.
>
>I guess the problem was this new MST feature means that now I have 5 HDMI
>outputs showing up, which is too many.

Yes, in dynamic mode, there are 5 HDMI/DP outputs for the compatibility
with pulseaudio.

Regards,
Libin

>
>Sorry for the noise.