TP-Link TL-WN722N driver stopped working

Question

Problem:

I have a TP-Link TL-WN722N external wireless card (basically an Atheros AR9271). It was working fine with my machine until today evening, where a power failure occured. On restarting, it does not work with the machine anymore. It does not show up on ifconfig or in the system tray (my machine only has an ethernet, and the WiFi option was completely absent).

In this question, Machine A refers to the problem machine: a Dell optiplex 3020 (ubuntu 16.04). Machine B is a test machine: a Dell optiplex 3040 (ubuntu 16.04) on which the adapter works without a hitch.

Tried so far:

• Rebooted multiple times out of frustration. No change
• Tried different usb ports. No change.
• Saw this thread, which provided some info on how to proceed with diagonostics (all of this is done on machine A)
  • lsusb registers the device (bus 003, device 009)

Bus 002 Device 002: ID 8087:8000 Intel Corp.
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:8008 Intel Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 007: ID 413c:301a Dell Computer Corp.
Bus 003 Device 008: ID 413c:2113 Dell Computer Corp.
Bus 003 Device 009: ID 0cf3:9271 Atheros Communications, Inc. AR9271 802.11n
Bus 003 Device 010: ID 1949:0004 Lab126, Inc. Amazon Kindle 3/4/Paperwhite
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

• lsmod lists ath9k_htc as a driver

ath9k_htc              77824  0
ath9k_common           36864  1 ath9k_htc
ath9k_hw              479232  2 ath9k_common,ath9k_htc
ath                    32768  3 ath9k_common,ath9k_htc,ath9k_hw
mac80211              741376  1 ath9k_htc
cfg80211              565248  4 ath,ath9k_common,mac80211,ath9k_htc

• loading the driver with sudo modprobe ath9k_htc gives an error, as reported by dmesg:

[  779.021924] usb 3-4: New USB device found, idVendor=0cf3, idProduct=9271
[  779.021933] usb 3-4: New USB device strings: Mfr=16, Product=32, SerialNumber=48
[  779.021939] usb 3-4: Product: USB2.0 WLAN
[  779.021944] usb 3-4: Manufacturer: ATHEROS
[  779.021948] usb 3-4: SerialNumber: 12345
[  779.022695] usb 3-4: ath9k_htc: Firmware ath9k_htc/htc_9271-1.4.0.fw requested
[  779.304846] usb 3-4: ath9k_htc: Transferred FW: ath9k_htc/htc_9271-1.4.0.fw, size: 51008
[  779.557139] ath9k_htc 3-4:1.0: ath9k_htc: HTC initialized with 33 credits
[  885.709381] ath9k_htc: Failed to initialize the device
[  885.709604] usb 3-4: ath9k_htc: USB layer deinitialized

• Control experiment: Testing if it is not a hardware problem: I plugged the wifi module into machine B and it worked just fine. Here are some diagonostics from B using dmesg

[  204.816781] usb 1-2: ath9k_htc: Firmware ath9k_htc/htc_9271-1.4.0.fw requested
[  204.816927] usbcore: registered new interface driver ath9k_htc
[  205.110170] usb 1-2: ath9k_htc: Transferred FW: ath9k_htc/htc_9271-1.4.0.fw, size: 51008
[  205.362327] ath9k_htc 1-2:1.0: ath9k_htc: HTC initialized with 33 credits
[  205.631164] ath9k_htc 1-2:1.0: ath9k_htc: FW Version: 1.4
[  205.631167] ath9k_htc 1-2:1.0: FW RMW support: On
[  205.631169] ath: EEPROM regdomain: 0x809c
[  205.631170] ath: EEPROM indicates we should expect a country code
[  205.631171] ath: doing EEPROM country->regdmn map search
[  205.631172] ath: country maps to regdmn code: 0x52
[  205.631173] ath: Country alpha2 being used: CN
[  205.631174] ath: Regpair used: 0x52
[  205.644713] ath9k_htc 1-2:1.0 wlx60e32712cd74: renamed from wlan0
[  386.990035] ath: phy1: Failed to wakeup in 500us

• Checked if drivers are not corrupted: The machine loads the driver in /lib/firmware/ath9k_htc/htc_9271-1.4.0.fw. I copied this file from machine B to A and ran a diff on them: both binaries are identical. As a double check, also compared /lib/firmware/htc_9271.fw on both machines with each other: they are also identical.
• Final resort: reinstalled drivers using sudo apt-get install --reinstall linux-firmware. This did not fix the problem.

I'm out of ideas. The drivers are installed and non-corrupted, yet loading the driver on A gives the non-verbose error Failed to initialize the device. This problem was also quite spontaneous and happened out of the blue: the adapter was working fine up until now. Any ideas for further diagonostics or a fix for this issue are appreciated.

Answer 1

I am not an expert on these matters, however:

I had a similar issue (without the lightning) at about the same date with my usb TP-Link TL-WN722N. I was running Ubuntu 16.04.6 LTS and module 4.4.0-186-generic. When I manually boot to 4.4.0-185-generic the TP-Link works fine. I hope this helps. Good luck.