Comment 4 for bug 1574079

I can confirm this fwupd issue for a different USB audio device, a PreSonus AudioBox 1818 VSL.

When I connect the card I get this in /var/log/syslog [1] [2]:

Apr 24 15:41:47 yogamme kernel: [ 34.958299] usbcore: registered new interface driver snd-usb-audio
Apr 24 15:41:47 yogamme org.freedesktop.fwupd[706]: (fwupd:1806): As-CRITICAL **: as_store_get_app_by_provide: assertion 'value != NULL' failed
Apr 24 15:41:47 yogamme systemd-udevd[2129]: Process '/usr/sbin/alsactl -E HOME=/run/alsa restore 2' failed with exit code 99.
Apr 24 15:41:50 yogamme gnome-session[1421]: (gnome-software:1739): Gs-WARNING **: failed to get updates: no results to show
Apr 24 15:41:52 yogamme kernel: [ 39.853364] usb 1-1.2: 2:2: cannot set freq 44100 (v2): err -110
Apr 24 15:41:52 yogamme kernel: [ 39.878675] usb 1-1.2: 2:2: usb_set_interface failed (-71)
Apr 24 15:41:52 yogamme kernel: [ 39.882926] usb 1-1.2: 2:2: usb_set_interface failed (-71)
Apr 24 15:41:52 yogamme kernel: [ 39.887176] usb 1-1.2: 2:2: usb_set_interface failed (-71)
...

Running `alsamixer` and selecting the USB sound card causes alsamixer to abort with a "protocol error".

If I do `sudo killall fwupd` and reconnect the USB sound card, everything works fine. It seems that fwupd is interfering with ALSA gaining control of the sound card.

[1]: My Thinkpad Yoga 14 laptop has USB 3.0 ports, but one can force them to behave as 2.0 ports via a BIOS/UEFI setting. The syslog excerpt is for USB 2.0 mode; in 3.0 mode an additional log message mentioning "URB transfer length is wrong, xHC issue?" appears among the usb_set_interface messages.
[2]: The gnome-software warning *is* related to fwupd - https://github.com/hughsie/fwupd mentions GNOME software as "the only graphical frontend available" for fwupd at present.