Bug 54029

Just a few more details:
 * once properly configured on the pulseaudio server, unplugging and replugging works fine as long as the server keeps running.
 * sometimes (but not always), when it fails to configure, the kernel spits this message:
4:1:1: usb_set_interface failed (-71)

Could you attach two pulseaudio logs: one where you start pulseaudio with the sound card plugged in (the working case), and one where you start pulseaudio with the sound card unplugged and then plug it in?

Instructions for getting the verbose log: https://wiki.ubuntu.com/PulseAudio/Log

Created attachment 66102 [details]
Log of pulseaudio server when doing hotplug (failure)

Created attachment 66103 [details]
Log of pulseaudio server when doing coldplug (succes)

Created attachment 66104 [details] [review]
Log diff between hotplug and coldplug

Here are the logs and the diff of them when attaching the Bose companion 5 with hotplug and coldplug

With coldplugging pulseaudio successfully opens the "surround41:1" device, but with coldplugging there's this:

D: [pulseaudio] alsa-mixer.c: Looking at profile output:analog-surround-41
D: [pulseaudio] alsa-mixer.c: Checking for playback on Analog Surround 4.1 (analog-surround-41)
D: [pulseaudio] alsa-util.c: Trying surround41:1 with SND_PCM_NO_AUTO_FORMAT ...
I: [pulseaudio] (alsa-lib)confmisc.c: Unable to find definition 'cards.USB-Audio.pcm.surround51.0:CARD=1'
I: [pulseaudio] (alsa-lib)conf.c: function snd_func_refer returned error: No such file or directory
I: [pulseaudio] (alsa-lib)conf.c: Evaluate error: No such file or directory
I: [pulseaudio] (alsa-lib)pcm.c: Unknown PCM surround41:1
I: [pulseaudio] alsa-util.c: Error opening PCM device surround41:1: No such file or directory

It's not only about "surround41", none of the device names except "hw" is found.

This looks like alsa bug. The configuration doesn't seem to be ready at the time when the card becomes available. I'm pretty clueless how this can be possible - I have always imagined that the alsa configuration is static. I don't understand why "cards.USB-Audio.pcm.surround51.0:CARD=1" would not exist when "hw:1" is available.

(In reply to comment #6)
> With coldplugging pulseaudio successfully opens the "surround41:1" device, but
> with coldplugging there's this:

The second "coldplugging" was of course supposed to be "hotplugging".

Indeed, it seems strange that surround41 is not found while hw:1 is. I tried to check with "aplay -L" just after plugging the device in, and they seem to all appear simultaneously.

Is there a way to force pulseaudio to try the initialization again a little bit after (e.g., with pacmd)?

# aplay -L
null
    Discard all samples (playback) or generate zero samples (capture)
pulse
    PulseAudio Sound Server
default:CARD=Intel
    HDA Intel, AD198x Analog
    Default Audio Device
sysdefault:CARD=Intel
    HDA Intel, AD198x Analog
    Default Audio Device
front:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    Front speakers
surround40:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    4.0 Surround output to Front and Rear speakers
surround41:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
dmix:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    Direct sample mixing device
dsnoop:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    Direct sample snooping device
hw:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    Direct hardware device without any conversions
plughw:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    Hardware device with all software conversions
default:CARD=Audio
    Bose USB Audio, USB Audio
    Default Audio Device
sysdefault:CARD=Audio
    Bose USB Audio, USB Audio
    Default Audio Device
front:CARD=Audio,DEV=0
    Bose USB Audio, USB Audio
    Front speakers
surround40:CARD=Audio,DEV=0
    Bose USB Audio, USB Audio
    4.0 Surround output to Front and Rear speakers
surround41:CARD=Audio,DEV=0
    Bose USB Audio, USB Audio
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Audio,DEV=0
    Bose USB Audio, USB Audio
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Audio,DEV=0
    Bose USB Audio, USB Audio
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Audio,DEV=0
    Bose USB Audio, USB Audio
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=Audio,DEV=0
    Bose USB Audio, USB Audio
    IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=Audio,DEV=0
    Bose USB Audio, USB Audio
    Direct sample mixing device
dsnoop:CARD=Audio,DEV=0
    Bose USB Audio, USB Audio
    Direct sample snooping device
hw:CARD=Audio,DEV=0
    Bose USB Audio, USB Audio
    Direct hardware device without any conversions
plughw:CARD=Audio,DEV=0
    Bose USB Audio, USB Audio
    Hardware device with all software conversions

After reading the log message once again, I just realized it contained the answer to my previous question ;-)
So, after a hotplug failure, and making sure that everything is settled down in ALSA, I used pacmd to load the module again:
>>> load-module module-alsa-card device_id="1" name="usb-Bose_Corporation_Bose_USB_Audio-00-Audio" card_name="alsa_card.usb-Bose_Corporation_Bose_USB_Audio-00-Audio" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes card_properties="module-udev-detect.discovered=1"
Module load failed.

It fails exactly the same way as during hotplug.

It's odd that it fails when loading module-alsa-card manually. The only explanation that I can think of is that the card gets somehow permanently mis-initialized if pulseaudio tries to use it too soon. Some things to test that theory: once you have done a failed hotplug attempt, and left the card plugged in, does it also fail if you unload module-udev-detect and load it again? If that fails, does it fail if you restart pulseaudio (without unplugging the card at any point)?

What about "speaker-test --channels=5 --device=surround41:1", does it work after a failed hotplug attempt?

Took me quite a long time to test. I feel there are actually two bugs. In addition to this pulseaudio bug, it seems that in some _rare_ cases the kernel fails to initialize the card correctly. When this happens, dmesg is full of such lines:
[28853.024822] 2:1:1: usb_set_interface failed (-71)

Then ALSA lists the device correctly but is unable to play anything on it (on any profile). Again, that's happening pretty rarely (~ once every 20 plug-in's). For the rest of this bug report, I'll just ignore this "kernel bug", assuming they are not related.


Back to the pulseaudio bug, I tested to do a hotplug leading to an initialization failure and then trying to use the card:
 * "speaker-test --channels=5 --device=surround41:1" works fine
 * unloading/reloading module module-udev-detect doesn't help (same error)
 * unloading the other module-alsa-card (for the internal card) fixes the problem! 

The conclusion is that the card does not seem mis-initialized, but more a problem with multi-load of  module-alsa-card. After a failure hotplug I can do this:
pacmd
unload-module 4  # that's the module-alsa-card for the Intel card
load-module module-alsa-card device_id="1" name="usb-Bose_Corporation_Bose_USB_Audio-00-Audio" card_name="alsa_card.usb-Bose_Corporation_Bose_USB_Audio-00-Audio" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes
=> the Bose card is ready

Alternatively, after unloading module-alsa-card it's possible to unload/load module-udev-detect, and you get both cards working (like a coldplug).

Does this hint on where could be laying the bug?

My guess is that when libasound reads the configuration too early, the configuration is somehow not ready yet, and the unfinished configuration is then cached by libasound so that as long as libasound is being linked to the pulseaudio process, the configuration never gets updated. Once you unload all modules that use libasound (i.e. all module-alsa-card instances), then libasound gets unlinked too from the pulseaudio process. Subsequent loading of module-alsa-card works, because now libasound properly reloads the configuration which is ready at this point.

So, I blame alsa for everything... That's based on guessing only, though, so I'll keep this bug open here at PulseAudio side too, in case someone wants to dig deeper.

You can report the problem on the alsa-devel mailing list.

Created attachment 123387 [details]
Patch that fixes the bug

It was indeed a bug in alsa-lib.

ALSA patch got rejected, they want this feature to be opt-in via new API.

http://mailman.alsa-project.org/pipermail/alsa-devel/2016-May/107816.html

you have post output of alsa-info.sh and lsusb -vvvv


if your usb audio does not support stereo, it is a bug of combine sink include any slave whech does not support stereo

https://bugs.freedesktop.org/show_bug.cgi?id=88265#c5


as your boss companion 5 does not support stereo but only 6 channels 

your ad1981 does not support 6 channels


combine sink may need to drop slave

This is now fixed in the "next" branch, meaning that PulseAudio 10.0 will have the fix: https://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/?id=efb14524a210e84fff573753f697b3c9baaa67a3

(In reply to Tanu Kaskinen from comment #17)
> This is now fixed in the "next" branch, meaning that PulseAudio 10.0 will
> have the fix:
> https://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/
> ?id=efb14524a210e84fff573753f697b3c9baaa67a3

The link is broken, here's a working link: https://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/?id=768c80f3c35da28f10a293ffa62c0e092db65db5

*** Bug 98401 has been marked as a duplicate of this bug. ***