rtl8811cu Based on rtl8821cu

Background

I bought an USB-wifi-adapter "TP-Link TL-WDN5200H" for my ubuntu server, whose core chip is "RTL8811CU" (ID: 0x0bda:0xc811) by The Realtek Corp., but this product only has official driver for WINDOWS system.

To make it work on ubuntu, I have searched for many relavent guides on the Internet, such as Driver for rtl8811cu? - Ubuntu Forums and TP-LINK TL-WDN5200 usb wifi adapter install on ubuntu?. But they didn't solve my problem until I found that "rtl8821cu driver source code contains some support for rtl8811cu" in alteman's rtl8821cu repo as follow.

#ifdef CONFIG_RTL8821C
	/*=== Realtek demoboard ===*/
	...
	{USB_DEVICE_AND_INTERFACE_INFO(USB_VENDER_ID_REALTEK, 0xC811, 0xff, 0xff, 0xff), .driver_info = RTL8821C}, /* 8811CU */
	...
	/*=== Customer ID ===*/
#endif

I changed a little in Makefile of alteman's repo for compiling on i386-PC platform.

And finally, the compiled driver can drive my USB-wifi-adapter on ubuntu.

How to do

Install driver

copy the whole repo to your PC, enter (your_dir)/rtl8821cu/, open a terminal and type:

make
sudo make install
sudo modprobe 8821cu

the driver installed.

Plug your USB-wifi-adapter into your PC

If wifi can be detected, congratulations. If not, maybe you need to switch your device usb mode by the following steps in terminal:

1. find your usb-wifi-adapter device ID, like "0bda:1a2b", by type:

lsusb

2. switch the mode by type: (the device ID must be yours.)

sudo usb_modeswitch -KW -v 0bda -p 1a2b

It should work.

Something more

I think this driver source code can be compiled for a series of Realtek wifi devices by minor changes with Makefile.