解决TP-LINK无线网卡在debian上无法识别的问题

TP-LINK无线网卡   tl-wn721n 驱动问题

问题描述：在debian系统上插入无线网卡后，系统没有任何反映。

使用dmesg发现该无线网卡已经被识别了，只是在/lib/firmware/目录下没有找到htc_9271.fw文件

[ 6372.304464] usb 2-6: USB disconnect, device number 4
[ 6927.052039] usb 2-5: new high-speed USB device number 5 using ehci_hcd
[ 6927.200902] usb 2-5: New USB device found, idVendor=0cf3, idProduct=9271
[ 6927.200906] usb 2-5: New USB device strings: Mfr=16, Product=32, SerialNumber=48
[ 6927.200910] usb 2-5: Product: USB2.0 WLAN
[ 6927.200912] usb 2-5: Manufacturer: ATHEROS
[ 6927.200914] usb 2-5: SerialNumber: 12345
[ 6927.203718] usb 2-5: ath9k_htc: Firmware - htc_9271.fw not found
[ 6927.203731] ath9k_htc: probe of 2-5:1.0 failed with error -22

在网上下载这个文件（http://dl.dbank.com/c0jiugspbr），放入/lib/firmware/，拔掉无线网卡再插上，提示信息如下，link is not ready。此时发现已经可以用无线网卡了

7127.561854] usb 2-6: ath9k_htc: USB layer initialized
[ 7127.568367] cfg80211: Regulatory domain changed to country: CN
[ 7127.568370] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
[ 7127.568374] cfg80211: (2402000 KHz - 2482000 KHz @ 40000 KHz), (N/A, 2000 mBm)
[ 7127.568377] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (N/A, 3000 mBm)
[ 7127.990370] ADDRCONF(NETDEV_UP): wlan0: link is not ready