Bug 505300

Summary:	GPU monitor function wakes up discrete NVIDIA GPU on multi-GPU system
Product:	[Applications] plasma-systemmonitor	Reporter:	Kimiblock Moe <kimiblock>
Component:	general	Assignee:	KSysGuard Developers <ksysguard-bugs>
Status:	RESOLVED FIXED
Severity:	normal	CC:	ahiemstra, nate, olib141, plasma-bugs-null
Priority:	NOR	Keywords:	efficiency-and-performance, regression
Version First Reported In:	6.3.91
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Kimiblock Moe 2025-06-07 08:30:46 UTC

SUMMARY
The default GPU usage widget wakes up the NVIDIA discrete GPU in a hybrid graphics laptop.

STEPS TO REPRODUCE
1. Install NVIDIA drivers in hybrid graphics mode
2. Launch System Monitor

OBSERVED RESULT
GPU wakes up as reported by "cat /sys/class/drm/card*/device/power_state"

EXPECTED RESULT
System Monitor does not wake up discrete GPU if the GPU is in D3cold power state.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux rolling w/ KDE Unstable repo
KDE Plasma Version: 6.3.91
KDE Frameworks Version: 6.14.0
Qt Version: 6.9.1

ADDITIONAL INFORMATION
The power state of the GPU can be determined by "/sys/class/drm/card*/device/power_state"

The former one should show D3cold and "/proc/driver/nvidia/gpus/*/power" should show the following when a laptop support such power save feature:

Runtime D3 status:          Enabled (fine-grained)
Video Memory:               Off

Comment 1 Arjen Hiemstra 2025-06-10 13:23:26 UTC

For NVidia GPUs, we don't touch the GPU directly, we just run the nvidia-smi tool to collect statistics. If that tool wakes up the GPU then there's not a whole lot we can do on our end to fix that.

Comment 2 Nate Graham 2025-06-10 13:35:39 UTC

See also:
- https://forums.developer.nvidia.com/t/nvidia-smi-keeps-gpu-awake-with-on-demand-prime-profile/200641
- https://forums.developer.nvidia.com/t/whats-waking-up-my-card-and-how-can-i-get-it-into-a-powered-off-state-when-using-on-demand/189005

Comment 3 Kimiblock Moe 2025-06-10 15:27:37 UTC

(In reply to Arjen Hiemstra from comment #1)
> For NVidia GPUs, we don't touch the GPU directly, we just run the nvidia-smi
> tool to collect statistics. If that tool wakes up the GPU then there's not a
> whole lot we can do on our end to fix that.

Yeah. Though the NVIDIA-smi thing will probably not fix this in a very long time. Considering many people do use hybrid graphics laptop it may be better to not invoke it until runtime status switches to D0? It’ll stop the discrete GPU from draining the battery.

Comment 4 Oliver Beard 2025-06-11 14:10:56 UTC

(In reply to Kimiblock Moe from comment #3)
> Considering many people do use hybrid graphics laptop it may be better
> to not invoke it until runtime status switches to D0? It’ll stop the discrete
> GPU from draining the battery.

It would continue to drain the battery afterwards. The fix needs to come from nvidia-smi.