我曾经在 Kubuntu 14.04 上愉快地使用过 TP-LINK TL-WN722N USB wifi 适配器。现在它突然停止工作了。当我插入它时，/var/log/syslog 显示如下内容：
Sep 30 20:34:08 meles kernel: [47010.291060] usb 3-2: new high-speed USB device number 13 using xhci_hcd
Sep 30 20:34:08 meles kernel: [47010.319034] usb 3-2: New USB device found, idVendor=0cf3, idProduct=9271
Sep 30 20:34:08 meles kernel: [47010.319049] usb 3-2: New USB device strings: Mfr=16, Product=32, SerialNumber=48
Sep 30 20:34:08 meles kernel: [47010.319055] usb 3-2: Product: USB2.0 WLAN
Sep 30 20:34:08 meles kernel: [47010.319059] usb 3-2: Manufacturer: ATHEROS
Sep 30 20:34:08 meles kernel: [47010.319063] usb 3-2: SerialNumber: 12345
Sep 30 20:34:08 meles kernel: [47010.320884] usb 3-2: ath9k_htc: Firmware htc_9271.fw requested
Sep 30 20:34:08 meles ModemManager[802]: <warn> Couldn't find support for device at '/sys/devices/pci0000:00/0000:00:1c.2/0000:02:00.0/usb3/3-2': not supported by any plugin
Sep 30 20:34:08 meles kernel: [47010.784766] usb 3-2: ath9k_htc: Transferred FW: htc_9271.fw, size: 51272
Sep 30 20:34:08 meles kernel: [47011.020822] ath9k_htc 3-2:1.0: ath9k_htc: HTC initialized with 33 credits
Sep 30 20:34:09 meles kernel: [47011.250691] ath9k_htc 3-2:1.0: ath9k_htc: FW Version: 1.3
Sep 30 20:34:09 meles kernel: [47011.250701] ath: EEPROM regdomain: 0x809c
Sep 30 20:34:09 meles kernel: [47011.250704] ath: EEPROM indicates we should expect a country code
Sep 30 20:34:09 meles kernel: [47011.250708] ath: doing EEPROM country->regdmn map search
Sep 30 20:34:09 meles kernel: [47011.250711] ath: country maps to regdmn code: 0x52
Sep 30 20:34:09 meles kernel: [47011.250715] ath: Country alpha2 being used: CN
Sep 30 20:34:09 meles kernel: [47011.250717] ath: Regpair used: 0x52
Sep 30 20:34:09 meles kernel: [47011.254919] ieee80211 phy15: Atheros AR9271 Rev:1
Sep 30 20:34:09 meles NetworkManager[1076]: <info> (wlan1): using nl80211 for WiFi device control
Sep 30 20:34:09 meles NetworkManager[1076]: <info> (wlan1): driver supports Access Point (AP) mode
Sep 30 20:34:09 meles NetworkManager[1076]: <info> (wlan1): new 802.11 WiFi device (driver: 'ath9k_htc' ifindex: 18)
Sep 30 20:34:09 meles NetworkManager[1076]: <info> (wlan1): exported as /org/freedesktop/NetworkManager/Devices/16
Sep 30 20:34:09 meles NetworkManager[1076]: <info> (wlan1): device state change: unmanaged -> unavailable (reason 'managed') [10 20 2]
Sep 30 20:34:09 meles NetworkManager[1076]: <info> (wlan1): bringing up device.
Sep 30 20:34:09 meles kernel: [47011.344907] usb 3-2: USB disconnect, device number 13
Sep 30 20:34:09 meles kernel: [47011.843938] ath: phy15: Chip reset failed
Sep 30 20:34:09 meles kernel: [47011.843951] ath: phy15: Unable to reset channel (2412 Mhz) reset status -22
Sep 30 20:34:09 meles kernel: [47011.843980] ath: phy15: Unable to set channel
Sep 30 20:34:09 meles kernel: [47011.945316] ath: phy15: RX failed to go idle in 10 ms RXSM=0xeaffffff
Sep 30 20:34:09 meles kernel: [47011.946506] IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready
Sep 30 20:34:09 meles kernel: [47011.955443] ath: phy15: Failed to wakeup in 500us
Sep 30 20:34:09 meles kernel: [47012.056695] ath: phy15: RX failed to go idle in 10 ms RXSM=0xe41da337
Sep 30 20:34:09 meles kernel: [47012.066754] ath: phy15: Failed to wakeup in 500us
Sep 30 20:34:09 meles kernel: [47012.168010] ath: phy15: RX failed to go idle in 10 ms RXSM=0xe41da337
Sep 30 20:34:10 meles kernel: [47012.192423] ath: phy15: Failed to wakeup in 500us
Sep 30 20:34:10 meles kernel: [47012.293854] ath: phy15: RX failed to go idle in 10 ms RXSM=0xb872752f
Sep 30 20:34:10 meles kernel: [47012.699081] ath: phy15: RX failed to go idle in 10 ms RXSM=0xb872752f
Sep 30 20:34:10 meles NetworkManager[1076]: <warn> (18) failed to find interface name for index
Sep 30 20:34:10 meles NetworkManager[1076]: (nm-system.c:766):nm_system_iface_get_flags: runtime check failed: (iface != NULL)
Sep 30 20:34:10 meles NetworkManager[1076]: <error> [1443638050.555454] [nm-system.c:768] nm_system_iface_get_flags(): (unknown): failed to get interface link object
Sep 30 20:34:10 meles NetworkManager[1076]: <warn> (18) failed to find interface name for index
Sep 30 20:34:10 meles NetworkManager[1076]: (nm-system.c:766):nm_system_iface_get_flags: runtime check failed: (iface != NULL)
Sep 30 20:34:10 meles NetworkManager[1076]: <error> [1443638050.555961] [nm-system.c:768] nm_system_iface_get_flags(): (unknown): failed to get interface link object
Sep 30 20:34:10 meles NetworkManager[1076]: <warn> (18) failed to find interface name for index
Sep 30 20:34:10 meles NetworkManager[1076]: (nm-system.c:766):nm_system_iface_get_flags: runtime check failed: (iface != NULL)
Sep 30 20:34:10 meles NetworkManager[1076]: <error> [1443638050.556434] [nm-system.c:768] nm_system_iface_get_flags(): (unknown): failed to get interface link object
Sep 30 20:34:10 meles NetworkManager[1076]: <warn> (18) failed to find interface name for index
Sep 30 20:34:10 meles NetworkManager[1076]: (nm-system.c:766):nm_system_iface_get_flags: runtime check failed: (iface != NULL)
Sep 30 20:34:10 meles NetworkManager[1076]: <error> [1443638050.557402] [nm-system.c:768] nm_system_iface_get_flags(): (unknown): failed to get interface link object
Sep 30 20:34:10 meles NetworkManager[1076]: <warn> (18) failed to find interface name for index
Sep 30 20:34:10 meles NetworkManager[1076]: (nm-system.c:766):nm_system_iface_get_flags: runtime check failed: (iface != NULL)
Sep 30 20:34:10 meles NetworkManager[1076]: <error> [1443638050.557948] [nm-system.c:768] nm_system_iface_get_flags(): (unknown): failed to get interface link object
Sep 30 20:34:10 meles ModemManager[802]: <info> (net/wlan1): released by modem /sys/devices/pci0000:00/0000:00:1c.2/0000:02:00.0/usb3/3-2
Sep 30 20:34:10 meles NetworkManager[1076]: <warn> (18) failed to find interface name for index
Sep 30 20:34:10 meles NetworkManager[1076]: (nm-system.c:766):nm_system_iface_get_flags: runtime check failed: (iface != NULL)
Sep 30 20:34:10 meles NetworkManager[1076]: <error> [1443638050.558456] [nm-system.c:768] nm_system_iface_get_flags(): (unknown): failed to get interface link object
Sep 30 20:34:10 meles NetworkManager[1076]: <warn> (18) failed to find interface name for index
Sep 30 20:34:10 meles NetworkManager[1076]: (nm-system.c:766):nm_system_iface_get_flags: runtime check failed: (iface != NULL)
Sep 30 20:34:10 meles NetworkManager[1076]: <error> [1443638050.559112] [nm-system.c:768] nm_system_iface_get_flags(): (unknown): failed to get interface link object
Sep 30 20:34:10 meles NetworkManager[1076]: <warn> (18) failed to find interface name for index
ETC。
它运行良好，然后我更新了内核（我想还有其他一些东西），拔掉电源，重新启动，它就不再工作了。我尝试用以前的内核启动，没有成功。我试过在另一台电脑上，它以前也可以工作（但距离我上次尝试已经过去很久了），结果是一样的。
设备没有任何亮起，我怀疑可能是设备本身出了问题，而不是操作系统出了问题。我还能做什么来找出问题所在吗？
答案1
鉴于您已在多台计算机上尝试过，并且插入时适配器上的灯没有亮，因此这几乎肯定是硬件问题。
usb 3-2: USB disconnect, device number 13此外，当操作系统尝试打开无线电时，该行表明适配器断开连接或出现故障。由于该消息来自 USB 驱动程序，因此几乎肯定是适配器的硬件问题。
如果您想进一步调试，可以尝试将其安装在 Windows 计算机上，但听起来适配器已经坏了。可能该换一个新的了。