RTX 5050 Blackwell mobile: driver unloads on AC unplug - PlatformRequestHandler SBIOS error

NVIDIA Open GPU Kernel Modules Version

595.71.05

Please confirm this issue does not happen with the proprietary driver (of the same version). This issue tracker is only for bugs specific to the open kernel driver.

• I confirm that this does not happen with the proprietary driver package.

Operating System and Version

Ubuntu 26.04 LTS

Kernel Release

7.0.0-22-generic

Please confirm you are running a stable release kernel (e.g. not a -rc). We do not accept bug reports for unreleased kernels.

• I am running on a stable kernel release.

Hardware: GPU

NVIDIA GeForce RTX 5050 Laptop GPU (Blackwell mobile)

Describe the bug

When the AC power adapter is unplugged while the system is running, nvidia-drm completely removes and unloads the GPU device. Running nvidia-smi after the event returns "No devices were found" until the system is rebooted.

dmesg logs capture the following failure sequence immediately upon pulling the plug:
[drm] [nvidia-drm] [GPU ID 0x00000100] Removing device
[drm] [nvidia-drm] [GPU ID 0x00000100] Unloading driver
NVRM: GPU0: PlatformRequestHandler failed to get platform power mode from SBIOS

Disabling fine-grained runtime power management via NVreg_DynamicPowerManagement=0x00 acts as a temporary workaround and prevents the crash, but forces the dGPU to constantly draw ~20W on battery.

To Reproduce

1. Boot the system on AC power with the open-source kernel modules active (595.71.05).
2. Verify the GPU is working correctly via nvidia-smi.
3. Unplug the AC power cord from the laptop.
4. Run nvidia-smi again. The terminal will output: "No devices were found".

Bug Incidence

Always

nvidia-bug-report.log.gz

1. Open your terminal and run: sudo nvidia-bug-report.sh

2. It will generate a file named nvidia-bug-report.log.gz in your current directory.

3. Drag and drop that file directly into this text area block on GitHub so it uploads as an attachment.

Note: Do not skip this step! As the text warns, the maintainers automatically close issues without this log attached.

More Info

System Model: Lenovo LOQ 15IRX10 (83JE)

Expected behavior: The driver should smoothly transition the mobile Blackwell GPU into a lower power state when switching to battery power, rather than failing the SBIOS platform power mode request and completely detaching the device node.

No source file or test is named. Start by reproducing the AC-unplug sequence, inspect the dmesg failure around PlatformRequestHandler and SBIOS power-mode handling, and generate the requested nvidia-bug-report.log.gz. Done means the GPU remains available to nvidia-smi after switching to battery power without requiring a reboot.