Created attachment 138649 [details]
Pulse log

Env:
Ubuntu 17.10

Kernel:
Linux stdcall 4.13.0-38-generic #43-Ubuntu SMP Wed Mar 14 15:20:44 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

There was an error from the kernel driver that caused the card to be unloaded from pulseaudio:

( 105.934|  15.016) D: [alsa-source-BeBoB] alsa-util.c: Got POLLERR from ALSA
( 105.934|   0.000) W: [alsa-source-BeBoB] alsa-util.c: Got POLLNVAL from ALSA
( 105.934|   0.000) D: [alsa-source-BeBoB] alsa-util.c: PCM state is RUNNING
( 105.934|   0.000) I: [alsa-source-BeBoB] (alsa-lib)pcm_hw.c: SNDRV_PCM_IOCTL_DROP failed (-19)
( 105.934|   0.000) I: [alsa-source-BeBoB] (alsa-lib)pcm_hw.c: SNDRV_PCM_IOCTL_PREPARE failed (-19)
( 105.934|   0.000) W: [alsa-source-BeBoB] alsa-util.c: Could not recover from POLLERR|POLLNVAL|POLLHUP with snd_pcm_prepare(): No such device
( 105.934|   0.000) I: [pulseaudio] module.c: Unloading "module-alsa-card" (index: #24).


What happens here? After unloading the card, 11 seconds pass and the card becomes available again. Did you unplug the card and then plug it back in? Based on your problem description, and the fact that this happens several times, I guess you didn't touch the sound card, it just periodically disappears and then comes back.

( 105.937|   0.000) I: [pulseaudio] module.c: Unloaded "module-alsa-card" (index: #24).
( 105.937|   0.000) D: [pulseaudio] module-udev-detect.c: /dev/snd/controlC2 is accessible: no
( 105.939|   0.002) I: [pulseaudio] module-udev-detect.c: Card /devices/pci0000:00/0000:00:01.1/0000:02:00.0/0000:03:00.0/fw2/fw2.0/sound/card2 removed.
( 117.137|  11.198) D: [pulseaudio] module-udev-detect.c: /dev/snd/controlC2 is accessible: yes
( 117.138|   0.000) D: [pulseaudio] module-udev-detect.c: /devices/pci0000:00/0000:00:01.1/0000:02:00.0/0000:03:00.0/fw2/fw2.0/sound/card2 is busy: no
( 117.138|   0.000) D: [pulseaudio] module-udev-detect.c: Loading module-alsa-card with arguments 'device_id="2"


34 seconds pass, and then the card is removed:

[log excerpt removed, because I don't think it is very informative after all]

5 seconds later the card is back:

[log removed]

21 seconds later the card goes away again:

[log removed]

...and 5 seconds later the card is back again:

[log removed]

So this "constant boot/reset loop" isn't something that happens non-stop, but every now and then (like twice a minute or so)?

In any case, this seems like a kernel problem. Here are some instructions for reporting alsa bugs: http://alsa-project.org/main/index.php/Bug_Tracking

I am also seeing this exact problem on my Scarlett 2i2 on Fedora 28 with kernel 4.17.2.. I get output for 10 to 30 seconds or so and then the I get a USB reset. Audio will start playing again once the reset is complete, but the cycle repeats.

However, for some reason if I have pavucontrol running I don't see any resets. It doesn't have to be in the foreground, just running minimized will prevent any playback issues from occurring. But as soon as I close the Volume Control app a reset will occur shortly after.

Agree that it sounds like a kernel issue but thought I'd add the info about pavucontrol in case it helps.

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This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/issues/150.