The Dropped Connections
Power management in Ubuntu, especially on laptops, is designed to aggressively cut power to unused peripherals. A common problem arises when using external USB hubs (like a multi-port dongle or a monitor with built-in USB ports). Ubuntu’s kernel may incorrectly identify the hub itself as “idle” if the connected devices (like a printer or external hard drive) haven’t transmitted data in a few seconds. The kernel then applies USB auto-suspend to the entire hub, instantly cutting power. When you finally try to print a document or access a file, the connection fails entirely because the hub has been put to sleep, forcing you to physically unplug and replug the device.
Keeping the Hub Powered
To ensure a stable connection to all your peripherals and stop Ubuntu from automatically suspending your USB hubs, you must disable the auto-suspend feature globally within the bootloader.
Open your terminal application (Ctrl+Alt+T). You need to edit the main GRUB configuration file with root privileges. Type: sudo nano /etc/default/grub. Look for the line starting with GRUB_CMDLINE_LINUX_DEFAULT=. You must add the specific kernel parameter to disable USB suspending to the end of the string, inside the quotation marks. Modify the line so it looks exactly like this: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash usbcore.autosuspend=-1". Press Ctrl+O to save your changes, hit Enter to confirm the filename, and press Ctrl+X to exit the Nano editor. Finally, tell the system to rebuild the boot menu by typing: sudo update-grub. Reboot your machine. Your USB hubs will now receive constant, uninterrupted power.