Lone audio device sudden problem after turn off - turn on again

Hello

After a recent update to my Fedora 36 plasma workstation an issue has developed with a FiiO K5 desktop pro headphone amplifier/DAC. It can be turned off (to preserve power and get rid of the blue ring LED), KDE then notifies that there’s no audio out device anymore* and audio cannot actually be played in for instance musikcube and Elisa.

(*This because I’ve used the profile “Off” for the other audio devices present since KDE will switch to an existing out device if present when the K5 is turned off and when the K5 is turned on again it will not switch back and I’ve found no indication that it can be made to do so.)

This has worked splendid up until rather recently. Now if the K5 is turned off and then on again Firefox cannot playback audio, the tabs do not have a speaker even. The K5 does appear as an audio out device as prior. Sometimes Elisa can play at this stage, sometimes it cannot (and then behaves as if the K5 is shut off, i.e says that a gstreamer plugin for flac is missing). If it can then after it has, Firefox can playback audio again.

Here are some journal entries:

When the K5 (as sole audio device in terms of not having the profile “off”) is physically turned off:

jul 17 11:41:30 feds kernel: usb 5-2: USB disconnect, device number 5  
jul 17 11:41:30 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "alsa_output.usb-GuangZhou_FiiO_Electronics_Co._Ltd_FiiO_K5_Pro-00.pro-output-0"  
jul 17 11:41:30 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "alsa_output.usb-GuangZhou_FiiO_Electronics_Co._Ltd_FiiO_K5_Pro-00.pro-output-0.monitor"  
jul 17 11:41:30 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "@DEFAULT_SINK@"  
jul 17 11:41:30 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "@DEFAULT_SOURCE@"  
jul 17 11:41:30 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "@DEFAULT_SINK@"  
jul 17 11:41:30 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "@DEFAULT_SOURCE@"  
jul 17 11:41:30 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "auto_null.monitor"

When the K5 is turned on again:

jul 17 11:42:02 feds kernel: usb 5-2: new high-speed USB device number 6 using xhci_hcd  
jul 17 11:42:03 feds kernel: usb 5-2: New USB device found, idVendor=2972, idProduct=0047, bcdDevice= 1.21  
jul 17 11:42:03 feds kernel: usb 5-2: New USB device strings: Mfr=1, Product=3, SerialNumber=0  
jul 17 11:42:03 feds kernel: usb 5-2: Product: FiiO K5 Pro  
jul 17 11:42:03 feds kernel: usb 5-2: Manufacturer: GuangZhou FiiO Electronics Co.,Ltd  
jul 17 11:42:03 feds kernel: usb 5-2: 1:3 : unsupported format bits 0x100000000  
jul 17 11:42:03 feds mtp-probe[5609]: checking bus 5, device 6: "/sys/devices/pci0000:00/0000:00:08.1/0000:0b:00.3/usb5/5-2"  
jul 17 11:42:03 feds mtp-probe[5609]: bus: 5, device: 6 was not an MTP device  
jul 17 11:42:03 feds mtp-probe[5624]: checking bus 5, device 6: "/sys/devices/pci0000:00/0000:00:08.1/0000:0b:00.3/usb5/5-2"  
jul 17 11:42:03 feds mtp-probe[5624]: bus: 5, device: 6 was not an MTP device  
jul 17 11:42:04 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "auto_null"  
jul 17 11:42:04 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "auto_null.monitor"  
jul 17 11:42:04 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "@DEFAULT_SINK@"  
jul 17 11:42:04 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "@DEFAULT_SOURCE@"  
jul 17 11:42:04 feds wireplumber[1819]: <WpSiStandardLink:0x563320491b60> 2 of 2 PipeWire links failed to activate  
jul 17 11:42:04 feds wireplumber[1819]: <WpSiStandardLink:0x563320491840> 2 of 2 PipeWire links failed to activate  
jul 17 11:42:04 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "@DEFAULT_SINK@"  
jul 17 11:42:04 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "@DEFAULT_SOURCE@"  
jul 17 11:42:04 feds plasmashell[1864]: org.kde.plasma.pulseaudio: No object for name "alsa_output.usb-GuangZhou_FiiO_Electronics_Co._Ltd_FiiO_K5_Pro-00.pro-output-0.monitor"

And when I then proceed to try and playback audio in firefox:

jul 17 11:43:08 feds wireplumber[1819]: <WpSiStandardLink:0x563320491d40> 2 of 2 PipeWire links failed to activate  
jul 17 11:43:15 feds plasmashell[3056]: [2022-07-17T09:43:15Z ERROR mp4parse] Found 2 nul bytes in "\0\0"  
jul 17 11:43:15 feds plasmashell[3056]: [2022-07-17T09:43:15Z ERROR mp4parse] Found 2 nul bytes in "\0\0"  
jul 17 11:43:15 feds plasmashell[3056]: [2022-07-17T09:43:15Z ERROR mp4parse] Found 2 nul bytes in "\0\0"  
jul 17 11:43:15 feds plasmashell[3056]: [2022-07-17T09:43:15Z ERROR mp4parse] Found 2 nul bytes in "\0\0"

An additional bit of info is that musikcube tends not to experience this issue - its output driver can be set to among others PipeWire as well as PulseAudio. I have it set to PulseAudio because with PipeWire the sound is choppy. If I set it to PipeWire when the issue is present (Elisa and FF cannot playback but the K5 is on and present under audio devices in the system settings) then it is as silent as Elisa and FF.

Has anyone any ideas? Hope ya’all are having a decent summer sunday : )