ubuntu disable charging on usb port (while tethering)

2 min read 22-10-2024

the ifix

ubuntu disable charging on usb port (while tethering)

When using your Ubuntu device as a USB tethering point, you may encounter a situation where your device starts to charge instead of simply transferring data. While this can be convenient for some, it can also drain the battery of the tethered device. Fortunately, there are methods to disable charging via the USB port while tethering. This article will guide you through the process, provide insights, and share practical examples.

The Problem Scenario

The issue arises when an Ubuntu system is used for USB tethering to share internet connectivity with another device. By default, the USB port may enable charging, causing the tethered device to charge while being connected. This can lead to unintended battery usage for devices that rely on the USB connection solely for data transfer.

Here’s an illustrative example of the code you might encounter or need when setting up your tethering configuration:

sudo nmcli device set <device-name> managed no

This command is typically used to manage network connections but does not address the issue of disabling charging while tethering.

Disabling USB Charging

To disable charging through the USB port on Ubuntu, you can make use of specific configurations in your system. Follow these steps to achieve this:

Check Kernel Parameters: Some Linux distributions provide a way to control USB power settings via kernel parameters. You can check if your system supports this by looking at the /sys/bus/usb/devices/ directory.
Modify the USB Power Configuration:
- Navigate to the USB device directory using:
```
cd /sys/bus/usb/devices/usbX/ # Replace 'X' with the specific bus number of your USB device
```
- You can write to power/control to change the power mode. Set it to 'suspend':
```
echo 'suspend' | sudo tee power/control
```
- Note that not all devices may support this and results can vary.
Using Udev Rules: Creating a udev rule can help automate this process. Create a new file in the udev rules directory:
```
sudo nano /etc/udev/rules.d/99-usb-tethering.rules
```
Add the following line to disable charging:
```
ACTION=="add", SUBSYSTEM=="usb", ATTR{idVendor}=="XXXX", ATTR{idProduct}=="YYYY", RUN+="/bin/sh -c 'echo '0' > /sys/bus/usb/devices/$kernel/power/control'"
```
Replace XXXX and YYYY with your USB device’s vendor ID and product ID, which can be found using the command lsusb.

Practical Example

For instance, if you are tethering an Android smartphone to your Ubuntu laptop, and you want to prevent the phone from charging, you might want to check the vendor and product IDs first:

lsusb

Assuming the output shows:

Bus 001 Device 002: ID 18d1:4ee0 Google Inc.

You would replace XXXX with 18d1 and YYYY with 4ee0 in your udev rule.

Conclusion

Disabling charging while tethering on Ubuntu is achievable through careful configuration and modification of system parameters. By implementing the steps outlined above, you can enhance your tethering experience without worrying about draining the battery of the tethered device.

Additional Resources

By keeping these configurations in mind, you’ll be better equipped to manage your devices while utilizing USB tethering efficiently.

Feel free to share your experiences or reach out if you have additional questions regarding USB tethering or managing power settings in Ubuntu!