Installing Bluetooth Driver for EP-AC1661

I am using EP-AC1661 WiFi and bluetooth adapter. According to their website the driver is supported only for kernel version 2.6 .I am trying to install the drivers on ubuntu 18.04 with a kernel version 5.0.0.29-generic

when I run the command

sudo make install -s

I get an error

 rtk_coex.c:2532:2 :error: implicit declaration of function 'init_timer'; did you mean 'init_timers'? [-Werror=implicit-function-declaration]
init_timer(&btrtl_coex.polling_timer)

any pointers in how do I fix this issue?

Edit1: The result of lsusb

:~$ lsusb
Bus 002 Device 007: ID 0bda:c820 Realtek Semiconductor Corp.
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 008 Device 002: ID 046d:c52b Logitech, Inc. Unifying Receiver
Bus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 004: ID 04f3:0b23 Elan Microelectronics Corp.
Bus 001 Device 003: ID 0424:2137 Standard Microsystems Corp.
Bus 001 Device 002: ID 1307:0330 Transcend Information, Inc. 63-in-1 Multi-Card Reader/Writer
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 009 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 010 Device 002: ID 0424:5537 Standard Microsystems Corp.
Bus 010 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub

The result of tail -f /var/log/syslog

tail -f /var/log/syslog
Sep 23 16:17:42 blue kernel: [ 5578.720943] usb 2-6: new high-speed USB device number 8 using ehci-pci
Sep 23 16:17:43 blue kernel: [ 5578.877878] usb 2-6: New USB device found, idVendor=0bda, idProduct=c820, bcdDevice= 2.00
Sep 23 16:17:43 blue kernel: [ 5578.877881] usb 2-6: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Sep 23 16:17:43 blue kernel: [ 5578.877883] usb 2-6: Product: 802.11ac NIC
Sep 23 16:17:43 blue kernel: [ 5578.877885] usb 2-6: Manufacturer: Realtek
Sep 23 16:17:43 blue kernel: [ 5578.877887] usb 2-6: SerialNumber: FF
Sep 23 16:17:43 blue mtp-probe: checking bus 2, device 8: "/sys/devices/pci0000:00/0000:00:1d.7/usb2/2-6"
Sep 23 16:17:43 blue mtp-probe: bus: 2, device: 8 was not an MTP device
Sep 23 16:17:43 blue upowerd[1164]: unhandled action 'bind' on /sys/devices/pci0000:00/0000:00:1d.7/usb2/2-6
Sep 23 16:17:43 blue kernel: [ 5578.981975] [UFW BLOCK] IN=enp5s0 OUT= MAC=bc:ae:c5:1a:0e:f1:00:bb:c1:75:7a:46:08:00 SRC=10.1.10.68 DST=10.1.10.121 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=49755 PROTO=UDP SPT=8610 DPT=8612 LEN=40
Sep 23 16:17:43 blue kernel: [ 5578.992093] [UFW BLOCK] IN=enp5s0 OUT= MAC=bc:ae:c5:1a:0e:f1:00:bb:c1:75:7a:46:08:00 SRC=10.1.10.68 DST=10.1.10.121 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=56262 PROTO=UDP SPT=8610 DPT=8612 LEN=40

Edit2:Result of usb-device

usb-devices
T: Bus=02 Lev=01 Prnt=01 Port=05 Cnt=01 Dev#= 3 Spd=480 MxCh= 0
D: Ver= 2.00 Cls=ef(misc ) Sub=02 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=0bda ProdID=c820 Rev=02.00
S: Manufacturer=Realtek
S: Product=802.11ac NIC
S: SerialNumber=FF
C: #Ifs= 3 Cfg#= 1 Atr=a0 MxPwr=500mA
I: If#= 0 Alt= 0 #EPs= 3 Cls=e0(wlcon) Sub=01 Prot=01 Driver=(none)
I: If#= 1 Alt= 0 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=(none)
I: If#= 2 Alt= 0 #EPs= 6 Cls=ff(vend.) Sub=ff Prot=ff Driver=rtl8821cu

1 Answer

This bluetooth device is supported by Linux kernel as you can see in drivers/bluetooth/btusb.c.

/* Realtek Bluetooth devices */ { USB_VENDOR_AND_INTERFACE_INFO(0x0bda, 0xe0, 0x01, 0x01), .driver_info = BTUSB_REALTEK },

The meaning of (0x0bda, 0xe0, 0x01, 0x01) is exactly what you have in

Vendor=0bda Cls=e0(wlcon) Sub=01 Prot=01

You have a combo Wi-Fi + BT device, both parts are visible in usb-devices

I: If#= 2 Alt= 0 #EPs= 6 Cls=ff(vend.) Sub=ff Prot=ff Driver=rtl8821cu

is the Wi-Fi device. It loads rtl8821cu driver successfully.

I: If#= 0 Alt= 0 #EPs= 3 Cls=e0(wlcon) Sub=01 Prot=01 Driver=(none)

is the BT device. It doesn't load btusb driver for some reason.

The reasons might be:

1. Kernel doesn't properly handle combo devices. This can be tested by blacklisting rtl8821cu. It should load btusb. If this is the case, it is a kernel bug that should be reported.

2. You already installed some driver that blacklists btusb, but doesn't work.

If you get btusb loading, you need to make sure there is firmware in lib/firmware/rtl_bt. The file is called rtl8821a_config.bin.

This file hasn't been added to linux-firmware yet, but you can find it in the old driver that you downloaded previuosly, that didn't install.

I see a file there in linux/2017.../BT/2017...BT_ANDROID/rtkbt/system/etc/firmware/rtl8821a_config

Try to rename it to rtl8821a_config.bin and copy to /lib/firmware/rtl_bt.

If this file works, I'll send it upstream.