My Plantronics Blackwire C420-M seems to have the same problem:
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 1:1: cannot get freq at ep 0x4
usb 1-4.2: 1:1: cannot get freq at ep 0x4
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 1:1: cannot get freq at ep 0x4
usb 1-4.2: 1:1: cannot get freq at ep 0x4
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 1:1: cannot get freq at ep 0x4
usb 1-4.2: 1:1: cannot get freq at ep 0x4
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 2:1: cannot get freq at ep 0x84
user@linux:~$ uname -a
Linux linux 4.4.0-59-generic #80-Ubuntu SMP Fri Jan 6 17:47:47 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
user@linux:~$ lsusb | grep Plantronics
Bus 001 Device 005: ID 047f:aa15 Plantronics, Inc.
Can you please add the USB ID to sound/usb/quirks.c too?
My Plantronics Blackwire C420-M seems to have the same problem:
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 1:1: cannot get freq at ep 0x4
usb 1-4.2: 1:1: cannot get freq at ep 0x4
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 1:1: cannot get freq at ep 0x4
usb 1-4.2: 1:1: cannot get freq at ep 0x4
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 1:1: cannot get freq at ep 0x4
usb 1-4.2: 1:1: cannot get freq at ep 0x4
usb 1-4.2: 2:1: cannot get freq at ep 0x84
usb 1-4.2: 2:1: cannot get freq at ep 0x84
user@linux:~$ uname -a
Linux linux 4.4.0-59-generic #80-Ubuntu SMP Fri Jan 6 17:47:47 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
user@linux:~$ lsusb | grep Plantronics
Bus 001 Device 005: ID 047f:aa15 Plantronics, Inc.
Can you please add the USB ID to sound/usb/quirks.c too?