Public bug reported:
Ubuntu 26.04 LTS, desktop workstation (Dell Precision 3280 CFF) used headless
as an LXD host.
GPU: NVIDIA GB203GL [RTX PRO 4000 Blackwell SFF Edition] [10de:2c33] (rev a1)
audio function [10de:22e9], upstream bridge 00:01.1 [8086:462d]
Driver: nvidia-driver-595-open 595.84-0ubuntu0.26.04.1 (NVIDIA open kernel
modules 595.84)
NVreg_DynamicPowerManagement=0x02, nvidia-drm modeset=0 fbdev=0
With linux-image-7.0.0-28-generic (7.0.0-28.28) the dGPU cycles into runtime
suspend
normally. After booting linux-image-7.0.0-29-generic (7.0.0-29.29) the card
stays in
D0/active permanently with power/runtime_usage=1 and never suspends again.
Package idle
power measured at the wall rises from 10-14 W to about 22 W.
The reference (runtime_usage=1) is held by the nvidia driver itself: it
survives logging
out of the GNOME session, unloading nvidia_drm and nvidia_modeset, and
unloading all
nvidia modules is worse still (no driver = no P8, +14 W).
Cross-check isolating the kernel (same machine, same configuration):
kernel nvidia result
7.0.0-28.28 595.71.05 suspends normally (140 and 172 wakeups over two boots)
7.0.0-29.29 595.84 never suspends (3 wakeups, all within the first 15 s
of boot)
7.0.0-28.28 595.84 suspends normally <-- same driver as the failing case
Last row is the decisive one: identical driver 595.84, identical module set
(nvidia, nvidia_uvm, nvidia_modeset, nvidia_drm), identical configuration; only
the
kernel differs, and the GPU suspends again. The reverse pairing (7.0.0-29 with
595.71.05) is not testable, that driver version is no longer in the archive.
Steps to reproduce:
1. Boot 7.0.0-29-generic with nvidia-driver-595-open and
NVreg_DynamicPowerManagement=0x02, no CUDA workload, no display attached.
2. Leave the machine idle.
3. cat /sys/bus/pci/devices/0000:02:00.0/power_state -> D0
cat /sys/bus/pci/devices/0000:02:00.0/power/runtime_status -> active
cat /sys/bus/pci/devices/0000:02:00.0/power/runtime_usage -> 1
cat /sys/bus/pci/devices/0000:02:00.0/power/runtime_suspended_time ->
frozen
Expected (and observed on 7.0.0-28.28, ~150 s after boot):
power_state D3cold, runtime_status suspended, runtime_usage 0,
runtime_suspended_time 142242 ms vs runtime_active_time 8864 ms.
Audio function 0000:02:00.1 also D3cold/suspended.
Ruled out by measurement, not assumption: GUI session and its GPU clients
(gnome-shell/Xwayland/nautilus/gnome-remote-desktop), KMS modules, CUDA/UVM
context,
VRAM threshold (memory.used 2 MiB against the 200 MB threshold), missing or
changed
config files, nvidia-persistenced, GPU containers (stopped), d3cold_allowed (1
on GPU,
audio function and bridge), and running without the driver at all.
The changelog between 7.0.0-28.28 and 7.0.0-29.29 shows no PCI-PM, D3cold,
pcieport or
ASPM change (CVE fixes plus one amdgpu HMM fix), so the regression is
presumably a side
effect rather than an intended change.
Note on the attached apport data: it was collected while running the *working*
kernel
7.0.0-28-generic, because the machine is remote and 7.0.0-29 costs the extra
power. Happy
to reboot into 7.0.0-29 and attach a second set on request.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-28-generic 7.0.0-28.28
ProcVersionSignature: Ubuntu 7.0.0-28.28-generic 7.0.12
Uname: Linux 7.0.0-28-generic x86_64
NonfreeKernelModules: zfs
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: gdm-greeter 3041 F.... wireplumber
/dev/snd/controlC0: gdm-greeter 3041 F.... wireplumber
/dev/snd/seq: gdm-greeter 3003 F.... pipewire
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Mon Aug 17 20:25:43 2026
InstallationDate: Installed on 2026-07-05 (43 days ago)
InstallationMedia: Ubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423.1)
Lsusb:
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Lsusb-t:
/: Bus 001.Port 001: Dev 001, Class=root_hub, Driver=xhci_hcd/16p, 480M
/: Bus 002.Port 001: Dev 001, Class=root_hub, Driver=xhci_hcd/9p, 20000M/x2
MachineType: Dell Inc. Precision 3280 Compact
ProcEnviron:
LANG=en_US.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
ProcFB:
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-28-generic
root=/dev/mapper/ubuntu--vg-ubuntu--lv ro quiet
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
RfKill:
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/22/2026
dmi.bios.release: 1.24
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.24.1
dmi.board.name: 0H1DC6
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 3
dmi.chassis.vendor: Dell Inc.
dmi.ec.firmware.release: 1.16
dmi.modalias:
dmi:bvnDellInc.:bvr1.24.1:bd05/22/2026:br1.24:efr1.16:svnDellInc.:pnPrecision3280Compact:pvr:rvnDellInc.:rn0H1DC6:rvrA00:cvnDellInc.:ct3:cvr:sku0C81:pfaPrecision:
dmi.product.family: Precision
dmi.product.name: Precision 3280 Compact
dmi.product.sku: 0C81
dmi.sys.vendor: Dell Inc.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute
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https://bugs.launchpad.net/bugs/2163682
Title:
Regression 7.0.0-28.28 -> 7.0.0-29.29: NVIDIA dGPU never enters
runtime suspend (D3cold), idle power +8 W
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