On Thu, 2021-10-07 at 18:55 -0700, Jonathan Ryshpan wrote:
The stock Fedora-34 with pipewire allows some audio output from the speakers but with problems.  However the system with pipewire was so unstable that I was unable to investigate:

So I reverted to pulseaudio.  The audio is now stable, but the speakers are not recognized.  Here are suspicious sections of the starts of the journals for the two setups:

Today's upgrade has mostly but not completely cured the problem, at least for pulseaudio.  The speakers started working as soon as the upgrade had taken effect, even before a reboot.  I don't see what upgraded package could have caused the device to appear; the record of the upgrade is attached (dnf-upgrade-1021-10-08.txt).  Unfortunately, the computer audio system does not always recognize the Audioengine-2+ speakers. Maybe there is some kind of race condition.

Here are extracts from system journals showing two different boot sequences, one that works and one that doesn't:

A boot that works:
Oct 08 14:06:08 amito kernel: usb 3-14.1: New USB device found, idVendor=0a12, idProduct=4007, bcdDevice=14.86 
Oct 08 14:06:08 amito kernel: usb 3-14.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 
Oct 08 14:06:08 amito kernel: usb 3-14.1: Product: Audioengine 2+ 
Oct 08 14:06:08 amito kernel: usb 3-14.1: Manufacturer: Audioengine LLC 
Oct 08 14:06:08 amito kernel: usb 3-14.1: SerialNumber: AE202010001A2002 
Oct 08 14:06:08 amito kernel: hid-generic 0003:0A12:4007.0006: hiddev97,hidraw3: USB HID v1.11 Device [Audioengine LLC Audioengine 2+] on usb-0000:00:14.0-14.1/input2

The boot just before the one above, which doesn't work:
Oct 08 14:00:31 amito kernel: usb 3-14.1: new full-speed USB device number 8 using xhci_hcd 
Oct 08 14:00:31 amito kernel: usb 3-14.1: New USB device found, idVendor=0a12, idProduct=4007, bcdDevice=14.86 
Oct 08 14:00:31 amito kernel: usb 3-14.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 
Oct 08 14:00:31 amito kernel: usb 3-14.1: Product: Audioengine 2+ 
Oct 08 14:00:31 amito kernel: usb 3-14.1: Manufacturer: Audioengine LLC
Oct 08 14:00:31 amito kernel: usb 3-14.1: can't set config #1, error -71

-- 
Sincerely Jonathan Ryshpan <jonrysh@pacbell.net>

	Better to light a single candle than to curse the
	darkness.