Hello, list, I hope this is the right place to post this problem. Changes introduced in 5.4.11 (seemingly, in drivers/usb/core/config.c) cause problems with at least some models of USB sound cards. I have a Sound Devices USBPre2, a high quality sound card that until 5.4.10 always worked perfectly out of the box as a standard USB audio device. Beginning with 5.4.11 and up to 5.5.0, when the sound card is connected, dmesg shows: [ 1310.743135] usb 3-10.3: new high-speed USB device number 6 using xhci_hcd [ 1310.755472] usb 3-10.3: config 1 interface 2 altsetting 1 has a duplicate endpoint with address 0x85, skipping [ 1310.755474] usb 3-10.3: config 1 interface 2 altsetting 2 has a duplicate endpoint with address 0x85, skipping [ 1310.755852] usb 3-10.3: New USB device found, idVendor=0926, idProduct=0202, bcdDevice= 1.00 [ 1310.755853] usb 3-10.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 1310.755854] usb 3-10.3: Product: USBPre2 [ 1310.755855] usb 3-10.3: Manufacturer: Sound Devices [ 1310.755855] usb 3-10.3: SerialNumber: HB1116132005 [ 1310.756803] usb 3-10.3: 1:3 : UAC_AS_GENERAL descriptor not found [ 1310.757550] hid-generic 0003:0926:0202.0005: hiddev96: USB HID v1.01 Device [Sound Devices USBPre2] on usb-0000:00:14.0-10.3/input3 [ 1310.773161] systemd-udevd[3856]: controlC0: Process '/usr/sbin/alsactl restore 0' failed with exit code 99. No capture device is created under /dev/snd, and the card works only as a playback device. ls -l /dev/snd total 0 drwxr-xr-x 2 root root 60 feb 1 10:36 by-id drwxr-xr-x 2 root root 60 feb 1 10:36 by-path crw-rw----+ 1 root audio 116, 0 feb 1 10:36 controlC0 crw-rw----+ 1 root audio 116, 16 feb 1 10:36 pcmC0D0p crw-rw----+ 1 root audio 116, 1 feb 1 10:14 seq crw-rw----+ 1 root audio 116, 33 feb 1 10:14 timer aplay -l **** List of PLAYBACK Hardware Devices **** card 0: USBPre2 [USBPre2], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 arecord -l **** List of CAPTURE Hardware Devices **** --
