Ubuntu 16.04.3 LTS笔记本HDMI无法工作求助：Windows下可正常使用

Hey there, let’s get that HDMI port working on your Ubuntu laptop—since it’s fully functional in Windows, we know the hardware is solid, so we just need to iron out the OS-level kinks. Here’s a step-by-step breakdown to fix this:

1. Verify if Ubuntu detects your HDMI display first #

First up, let’s check if the system even sees the HDMI monitor. You can do this two ways:

• Graphically: Open System Settings → Displays. Look for a second screen icon—if it’s there, try toggling the “Mirror displays” option or dragging the screen to position it relative to your laptop display.
• Via command line: Run xrandr in the terminal. Look for an entry like HDMI-1 (name might vary, e.g., HDMI-2). If it says connected, the system detects it but isn’t outputting to it; if it says disconnected, we need to dig into drivers or hardware checks.

2. Update or switch your graphics drivers #

Ubuntu 16.04 often defaults to open-source graphics drivers, which can sometimes lack full HDMI support for certain GPUs. Let’s check and switch to a proprietary driver if needed:

1. Open Software & Updates → go to the Additional Drivers tab.
2. You’ll see a list of available drivers for your GPU (NVIDIA, AMD, or Intel). Select the one marked “Recommended” (usually a proprietary driver).
3. Click Apply Changes, wait for the installation to finish, then restart your laptop.

For Intel GPUs: The open-source drivers are usually reliable, but you can try updating them via sudo apt-get install xserver-xorg-video-intel to ensure you have the latest version for your 16.04 setup.

3. Manually enable HDMI output via command line #

If xrandr shows your HDMI display as connected but it’s not active, force it on with this command (adjust the display names to match your xrandr output):

xrandr --output HDMI-1 --auto --right-of eDP-1

• --auto sets the HDMI display to its native resolution.
• --right-of eDP-1 places it to the right of your laptop screen (replace eDP-1 with your laptop’s display name from xrandr, like LVDS-1).

You can also mirror displays with:

xrandr --output HDMI-1 --auto --same-as eDP-1

4. Rule out cable/port quirks #

Even though Windows works, Ubuntu can be pickier about HDMI cable quality. Try:

• Swapping to a high-speed HDMI cable (v1.4 or newer).
• Plugging the cable into a different HDMI port (if your laptop has multiple).
• Unplugging and re-plugging the cable after restarting Ubuntu.

5. Update your kernel #

Ubuntu 16.04’s default kernel might be outdated for newer GPU HDMI features. Install the latest LTS kernel backport with:

sudo apt-get update
sudo apt-get install linux-generic-hwe-16.04

Restart your laptop after installation and check the HDMI again.

6. Reset your display manager #

If you’re using the default Unity desktop, a glitch in the display manager could be blocking HDMI output. Restart it with:

sudo systemctl restart lightdm

You’ll be logged out temporarily—log back in and test the HDMI.

If none of these steps work, sharing the output of lspci | grep VGA (to show your GPU model) and the full xrandr output will help narrow down the issue further.

内容的提问来源于stack exchange，提问作者Ameer B. A. Alaasam