[Solved] After upgradeing Pop!_OS from 22.04 Jammy to 24.04 Noble on my System76 laptop, external monitor is no longer recognized

After upgradeing Pop!_OS from 22.04 Jammy to 24.04 Noble, external monitor is no longer recognized.md

Pop!_OS 24.04 Upgrade: External Monitor Not Working on System76 Laptop

Symptoms

After upgrading from Pop!_OS 22.04 to 24.04, an external monitor connected via HDMI stops working. The system behaves as if no monitor is plugged in and sends no video signal over HDMI.

Affected Hardware

System76 laptops with hybrid (dual) graphics — an Intel integrated GPU and a discrete NVIDIA GPU. The HDMI port on these laptops is physically wired to the NVIDIA discrete GPU, not the Intel integrated GPU.

Root Cause

The OS upgrade resets the system76-power graphics mode from hybrid to integrated. In integrated mode, the NVIDIA GPU is powered off entirely. Because the HDMI port is wired to the NVIDIA GPU, no signal is produced regardless of what is plugged in.

Diagnosis

Check your current graphics mode:

system76-power graphics

If it returns integrated and you have an external monitor that should work, this is likely your problem.

You can also confirm the NVIDIA driver is installed but not loaded:

lsmod | grep nvidia   # returns nothing in integrated mode
nvidia-smi            # fails in integrated mode

Solution

Switch to hybrid graphics mode, then reboot:

sudo system76-power graphics hybrid
sudo reboot

Available Graphics Modes

Mode	Description
integrated	Intel GPU only. NVIDIA powered off. HDMI does not work.
hybrid	Intel drives internal display; NVIDIA available for external displays and compute.
nvidia	NVIDIA drives everything. Higher power usage.
compute	Like integrated, but NVIDIA is available for compute (CUDA) only.

Notes

• This is not a driver issue. The NVIDIA driver (580 as of this writing) installs and builds correctly for the Pop!_OS 24.04 kernel. The modules simply are not loaded in integrated mode by design.
• If the issue recurs after a future upgrade, system76-power graphics is the first thing to check.
• When upgrading to Pop!_OS 24.04, System76 removed the GUI for setting the graphics mode (integrated, hybrid or nvidia). There's no place to see the setting or set this in the GUI now