Public bug reported:
Summary
NVIDIA GeForce GTX 950M remains runtime active in PRIME on-demand mode
on Kubuntu 26.04 LTS Wayland, even when the GPU is completely idle. The
cooling fan keeps running. Switching to PRIME Intel mode immediately
allows the fan to stop.
System
Kubuntu 26.04 LTS
KDE Plasma (Wayland)
Linux 7.0.0-27-generic
NVIDIA driver 580.159.03
Intel HD Graphics 530 + NVIDIA GeForce GTX 950M (Optimus)
Steps to reproduce
Install Kubuntu 26.04 LTS.
Install the proprietary NVIDIA 580 driver using "Additional Drivers".
Select PRIME "on-demand".
Reboot.
Do not start any application that uses the NVIDIA GPU.
Expected result
When the NVIDIA GPU is idle, it should enter the lowest possible runtime power
state (or otherwise power down sufficiently so that it no longer contributes to
cooling requirements), similar to the behavior observed on Ubuntu Desktop with
the same hardware.
Actual result
The NVIDIA GPU remains runtime active indefinitely.
Relevant outputs:
prime-select query
on-demand
cat /sys/bus/pci/devices/0000:01:00.0/power/runtime_status
active
cat /proc/driver/nvidia/gpus/0000:01:00.0/power
Runtime D3 status: Disabled by default
nvidia-smi
Shows:
GPU utilization: 0%
Memory usage: 0 MiB
No running GPU processes
Driver parameters:
DynamicPowerManagement: 3
Additional information
Wayland session
switcheroo-control is installed.
plasma-optimus was installed for testing but did not change the behavior.
nvidia-settings autostart was disabled for testing.
No user applications are using the NVIDIA GPU.
nvidia_drm.modeset=1 is enabled.
If I switch to:
sudo prime-select intel
and reboot, the NVIDIA driver is unloaded, the laptop becomes silent and
the cooling fan stops within a few seconds.
This suggests that the issue is specific to PRIME "on-demand" behavior
on this system rather than a hardware problem.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: nvidia-driver-580 580.159.03-0ubuntu0.26.04.1
ProcVersionSignature: Ubuntu 7.0.0-27.27-generic 7.0.6
Uname: Linux 7.0.0-27-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.34.0-0ubuntu2
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: KDE
Date: Mon Jul 13 03:09:14 2026
InstallationDate: Installed on 2026-07-05 (7 days ago)
InstallationMedia: Kubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423)
SourcePackage: nvidia-graphics-drivers-580
UpgradeStatus: No upgrade log present (probably fresh install)
** Affects: nvidia-graphics-drivers-580 (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
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https://bugs.launchpad.net/bugs/2160471
Title:
NVIDIA GTX 950M stays runtime active in PRIME on-demand on Kubuntu
26.04
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