Colibri i.MX6 Wifi Hot Plugging

cheesi · April 2, 2025, 10:32am

Hello!

We are currently in the process of migrating from our old 2.8 BSP to the latest 7.1 and have a couple of issues with WiFi, especially with Hot Plugging of the WiFi Dongle.

The following was tested with a Toradex BSP 7.1 console image, using a Colibri iMX6S, a Viola carrier board and LM816 USB WiFi dongle.

At first, the WiFi dongle is not connected:

root@colibri-imx6-11371969:~# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
2: end0: <BROADCAST,MULTICAST,DYNAMIC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
3: usb0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000

Then I configured the WiFi by writing a config file to /var/lib/connman/wifi.config:

[service_yourwifi]
Type = wifi
Name = SSID
Passphrase = password

At this point, scanning for WiFi obviously still fails, as I haven’t connected the dongle just yet (but our application is trying it anyway, so I have included it in my test case):

connmanctl> enable wifi
wifi is not available
connmanctl> scan wifi
Error /net/connman/technology/wifi: Method "Scan" with signature "" on interface "net.connman.Technology" doesn't exist

Then I connected the WiFi dongle, it shows up as a new network interface:

[  871.290592] usb 1-1: new high-speed USB device number 2 using ci_hdrc
[  871.491715] usb 1-1: New USB device found, idVendor=0bda, idProduct=8179, bcdDevice= 0.00
[  871.500176] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  871.507633] usb 1-1: Product: 802.11n NIC
[  871.517242] usb 1-1: Manufacturer: Realtek
[  871.523796] usb 1-1: SerialNumber: 00E04C0001
[  871.812588] usb 1-1: RTL8188EU rev D (TSMC) romver 0, 1T1R, TX queues 2, WiFi=1, BT=0, GPS=0, HI PA=0
[  871.822182] usb 1-1: RTL8188EU MAC: 34:c9:f0:91:22:24
[  871.827393] usb 1-1: rtl8xxxu: Loading firmware rtlwifi/rtl8188eufw.bin
[  871.847284] usb 1-1: Firmware revision 28.0 (signature 0x88e1)
[  872.508135] usbcore: registered new interface driver rtl8xxxu
[  872.644895] rtl8xxxu 1-1:1.0 wlu1: renamed from wlan0 (while UP)

root@colibri-imx6-11371969:~# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
2: end0: <BROADCAST,MULTICAST,DYNAMIC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
3: usb0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000
4: wlu1: <NO-CARRIER,BROADCAST,MULTICAST,DYNAMIC,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 34:c9:f0:91:22:24 brd ff:ff:ff:ff:ff:ff

Scanning for WiFi networks still fails though and it can’t connect to the WiFi network:

connmanctl> enable wifi
wifi is already enabled
connmanctl> scan wifi
Error /net/connman/technology/wifi: No carrier
connmanctl>

Now the interesting part: after a reboot connmanctl services shows all the WiFi networks it found. So it works, if the dongle was present during booting.

With the old BSP 2.8, this reboot was not required.

I also already tested with other hardware of the same type (other Colibri iMX6 etc.) and had the same issues.

tdx-info:

root@colibri-imx6-11371969:~# tdx-info

Software summary
------------------------------------------------------------
Bootloader:               U-Boot
Kernel version:           6.6.69-7.1.0-00039-g0f10503b36ba #1 SMP PREEMPT Thu Jan  2 09:32:11 UTC 2025
Kernel command line:      root=PARTUUID=1e49de5b-02 ro rootwait console=tty1 console=ttymxc0,115200
Distro name:              NAME="TDX Wayland with XWayland Upstream"
Distro version:           VERSION_ID=7.1.0-build.3
Distro variant:           -
Hostname:                 colibri-imx6-11371969
------------------------------------------------------------

Hardware info
------------------------------------------------------------
HW model:                 Toradex Colibri iMX6DL/S on Colibri Evaluation Board V3
Toradex version:          0077 V1.1A
Serial number:            11371969
Processor arch:           armv7l
------------------------------------------------------------

Best Regards,
Christian

ToradexAI · April 2, 2025, 10:33am

Hi, I’m the Toradex AI Assistant. The Toradex Support team will follow up with you shortly!

Did you like my answer?

Hello!

Thank you for reaching out with your question about using the LM816 USB WiFi dongle with Toradex’s Embedded Linux systems. Unfortunately, this dongle is specifically designed for Windows CE and is not recommended for use with Embedded Linux. However, there are several alternatives you can consider for your Linux-based system.

For a seamless experience, you might want to explore the built-in WiFi modules available with certain Colibri modules. These are supported by Toradex’s Embedded Linux BSPs, which provide out-of-the-box software support for specific WiFi modules. You can find more information on compatible products and configuration steps in the Toradex developer resources.

To configure WiFi on your Linux system, you can use the connman package, which is included in the Toradex Reference Images. Here’s a quick guide to get you started:

Open a terminal and enter connmanctl.
Enable WiFi by typing enable wifi.
Scan for available networks with scan wifi.
Turn on the agent with agent on.
List available services using services.

If you need to set up a static IP address, you will need to create specific configuration files in the connman directory. Detailed instructions can be found in the Toradex developer documentation.

I recommend checking the compatibility list to ensure you choose a WiFi solution that is fully supported by your Linux BSP version. This will help you avoid any potential issues with connectivity.

I hope this helps! If you have any more questions, feel free to ask.

Best regards,
Toradex AI Assistant.

Please, also check if these links can help you solve your problem:

Toradex’s Linux Images - How to connect to a Wi-Fi network | Toradex Developer Center.