nvidia: skip teardown in nv_pci_shutdown() while GPU is hibernate-suspended (fixes no power-off after hibernation)

[expaso]

Problem

With the documented hibernation setup (NVreg_PreserveVideoMemoryAllocations=1 + nvidia-hibernate.service), the system never powers off after the hibernation image has been written. The image is complete (resume works after a forced power-off), but the machine sits there with the last console line:

[nvidia-drm] Unloading driver

Reproduced every time on 610.57.04 and 615.71.09 with HibernateMode=shutdown (/sys/power/disk = shutdown). reboot mode and a failed ACPI S4 entry in platform mode go through the same kernel_power_off()/device_shutdown() path.

Root cause

1. nvidia-sleep.sh hibernate writes to /proc/driver/nvidia/suspend → nv_set_system_power_state() takes nv_system_pm_lock for write and suspends the GPU (NV_FLAG_SUSPENDED).
2. The kernel freezes devices (nv_pmops_freeze), takes the snapshot and thaws devices to write the image. nv_pmops_thaw() is a no-op, so the GPU stays suspended and nv_system_pm_lock stays write-locked for the rest of the hibernation.
3. After the image is written, kernel_power_off() → device_shutdown() → nv_pci_shutdown() → nv_pci_remove_helper() → nvidia_modeset_remove() → nvidia-drm unload: a full driver teardown against a suspended GPU, which never completes.

Fix

In nv_pci_shutdown(), if the device is still NV_FLAG_SUSPENDED, only clear bus mastering and return. The machine is about to lose power and the GPU state was already saved by the suspend path, so the teardown is neither needed nor possible. Normal shutdown/reboot are unaffected (the flag is not set then).

Testing

• ASUS ROG Zephyrus G16 (GU605CW), RTX 5080 Laptop GPU (GB203), hybrid with Intel iGPU
• Open kernel modules 615.71.09, Linux 7.3-rc5, Ubuntu 26.04, HibernateMode=shutdown
• Before: hang at "Unloading driver" on every hibernation (also with 610.57.04)
• After: powers off right after the image is written; resume works; normal shutdown/reboot unchanged

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