Comment 278 for bug 1667750

Tested another device against the applied patches to make sure the issue isn't related to the combination rt2800usb - usb host:
ID 7392:7710 Edimax Technology Co., Ltd Edimax Wi-Fi

[ 68.126337] usb 1-2: new high-speed USB device number 17 using xhci_hcd
[ 68.181565] usb 1-2: New USB device found, idVendor=7392, idProduct=7710, bcdDevice= 0.00
[ 68.181568] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 68.181571] usb 1-2: Product: Edimax Wi-Fi
[ 68.181573] usb 1-2: Manufacturer: MediaTek
[ 68.181575] usb 1-2: SerialNumber: 1.0
[ 68.398420] usb 1-2: reset high-speed USB device number 17 using xhci_hcd
[ 68.446602] mt7601u 1-2:1.0: ASIC revision: 76010001 MAC revision: 76010500
[ 68.473662] mt7601u 1-2:1.0: Firmware Version: 0.1.00 Build: 7640 Build time: 201302052146____
[ 69.461098] mt7601u 1-2:1.0: EEPROM ver:0d fae:00
[ 69.472103] mt7601u 1-2:1.0: EEPROM country region 01 (channels 1-13)
[ 70.152995] mt7601u 1-2:1.0: Warning: mt7601u_mcu_wait_resp retrying
[ 70.472567] mt7601u 1-2:1.0: Warning: mt7601u_mcu_wait_resp retrying
[ 70.792966] mt7601u 1-2:1.0: Warning: mt7601u_mcu_wait_resp retrying
[ 71.112927] mt7601u 1-2:1.0: Warning: mt7601u_mcu_wait_resp retrying
[ 71.432909] mt7601u 1-2:1.0: Warning: mt7601u_mcu_wait_resp retrying
[ 71.432913] mt7601u 1-2:1.0: Error: mt7601u_mcu_wait_resp timed out
[ 71.433388] xhci_hcd 0000:03:00.0: WARN Set TR Deq Ptr cmd failed due to incorrect slot or ep state.
[ 71.435442] xhci_hcd 0000:03:00.0: WARN Set TR Deq Ptr cmd failed due to incorrect slot or ep state.
[ 71.582930] mt7601u 1-2:1.0: Vendor request req:07 off:0080 failed:-71
[ 71.729217] mt7601u 1-2:1.0: Vendor request req:02 off:0080 failed:-71

After the device is unplugged, dmesg log is spammed:
[ 363.312561] mt7601u 1-2:1.0: Vendor request req:07 off:0730 failed:-71
[ 363.479252] mt7601u 1-2:1.0: Vendor request req:07 off:0730 failed:-71
[ 363.649243] mt7601u 1-2:1.0: Vendor request req:07 off:0730 failed:-71
...
[ 380.069000] mt7601u 1-2:1.0: Vendor request req:02 off:0080 failed:-71
[ 380.069055] mt7601u: probe of 1-2:1.0 failed with error -110
[ 380.069272] usb 1-2: USB disconnect, device number 90

@Bernhard: I can confirm missing Error message on some devices, too. The devices are not working.