As per https://www.raspberrypi.org/forums/viewtopic.php?t=15872, I believe the USB ID 0x05A7 0x1020 needs to be added to quirks.c in order for me to use my Bose Companion 5 speakers. Thanks!
usb 3-1.8: 1:1: cannot get freq at ep 0x1
...the same message will flood over dmesg.
Patched it by adding snd-usb-audio.quirk_alias to as a kernel parameter to behave like 0x047F 0x02F7 (described in Raspberry Pi forums).
With this patch, ALSA stops trying to read sample rate from device,
hence no more error messages.
dmesg output after applying the patch:
usb 3-1.8: device (05a7:1020): applying quirk alias 047f:02f7
Thanks, the patch below should fix the problem without quirk option.
I'll submit and merge to upstream later.
Created attachment 286615 [details]
Thanks for replying and applying a patch so fast!
FYI: After upgrading to newest kernel (5.4.8-arch1-1), my quirk alias is broken (again). There are no dmesg errors (e.g. "caonnot get freq at ep 0x1") though.
After further investigations dmesg is throwing: "perf: interrupt took too long (2514 > 2500), lowering kernel.perf_event_max_sample_rate to 79500" messages when the sound is dropping out.
Unplugging an re-plugging the powercable of the Bose Companion 5 speakers fixes the problem (temporarily).