求助：东芝A665-S6100X重启/休眠后以太网连接消失问题

Hey there, sorry to hear you're stuck with this annoying Ethernet issue on your Toshiba laptop—totally get why relying only on WiFi when you need faster speeds is frustrating. Since this works perfectly on Windows, it's clearly a Linux-specific driver or power management quirk, not a hardware problem. Let's go through actionable fixes that have resolved similar issues:

• Quick test: Reload the Ethernet driver
  First, identify your Ethernet adapter model with this command:

  lspci | grep Ethernet
  

  For most Toshiba A665 models, this will be a Realtek adapter using the r8169 driver. Try unloading and reloading the driver to restore connectivity immediately:

  sudo modprobe -r r8169 && sudo modprobe r8169
  

  If this brings back Ethernet, make the fix permanent by adding the driver to your startup modules:

  sudo nano /etc/modules
  

  Add r8169 to the end of the file, save (Ctrl+O) and exit (Ctrl+X). It will load automatically on next boot.

• Disable power management for Ethernet
  Ubuntu’s default power settings sometimes shut down the Ethernet adapter after sleep/hibernate. Tweak the NetworkManager config to prevent this:

  1. Open your Ethernet connection’s config file (replace <your-ethernet-name> with the actual name from NetworkManager):

     sudo nano /etc/NetworkManager/system-connections/<your-ethernet-name>
     

  2. Under the [802-3-ethernet] section, add this line:

     power-management=false
     

  3. Save the file and restart NetworkManager:

     sudo systemctl restart NetworkManager
     

• Update or roll back your kernel
  Ubuntu 16.04’s default kernel might have compatibility issues with older Ethernet hardware. Try upgrading to the latest stable LTS kernel for Xenial:

  sudo apt-get update && sudo apt-get install linux-generic-lts-xenial
  

  If the issue started after a kernel update, boot into an older kernel version from the GRUB menu (hold Shift during boot to access it) to test if that fixes things.

• Check BIOS power settings
  Sometimes BIOS-level power management can interfere with Linux’s ability to reinitialize the Ethernet adapter. Reboot your laptop and press F2 (Toshiba’s standard BIOS key) to enter setup. Look for options like LAN Power Management or Wake on LAN—make sure they’re set to Enabled or Always On (not power-saving modes). Save changes and reboot.

If none of these steps work, you could also try installing the proprietary Realtek driver for your adapter, but the above fixes should cover most cases for this laptop model.

内容的提问来源于stack exchange，提问作者Omar Cuba