Nvidia 920MX GPU Passthrough Guide for Proxmox
Nvidia 920MX GPU Passthrough Guide for Proxmox. Learn GPU Passthrough, Theming, and Virtualization with practical Proxmox steps.
Environment overview
Host: Proxmox VE 9.1 (Kernel 6.17+)
GPU: NVIDIA GeForce 920MX (GM108M - Maxwell)
Platform: Lenovo Laptop (Optimus / MUXless)
Guest: Linux (Kernel 6.19+)
Driver: NVIDIA 580.xx
The 60-second VBIOS timeout error
NVRM: GPU 0000:01:00.0: Failed to copy vbios to system memory.NVRM: GPU 0000:01:00.0: RmInitAdapter failed! (0x30:0xffff:1116)The 60-second delay usually means the guest driver is waiting for a working VBIOS response through ACPI _ROM or ROM BAR exposure, and initialization fails because of Optimus architecture constraints or power gating behavior.
Common causes on Maxwell mobile GPUs
- Optimus (MUXless) design prevents full dGPU ownership
- ACPI _ROM method not fully compatible with 580.xx driver
- ROM provided via fw_cfg rejected by newer driver validation
- Power management not disabled at host level
- Kernel 6.19+ behavioral changes affecting ACPI injection
Recommended debug checklist
- Confirm the dumped VBIOS is from cold boot (not extracted while driver loaded).
- Test with romfile= directly in hostpci instead of fw_cfg injection.
- Remove vendor/device spoofing temporarily to rule out validation conflicts.
- Try an older NVIDIA driver branch (535 or 550 series) inside the guest.
- Disable ASPM and power management in host kernel parameters.
- Verify IOMMU group isolation and ensure no iGPU dependencies remain attached.
Known limitation of Optimus laptops
MUXless systems route display output through the iGPU. Even if the dGPU initializes in the guest, it may never fully power up without embedded controller cooperation. Many Maxwell mobile GPUs cannot be reliably passed through unless the laptop BIOS provides discrete-only mode.
Frequently asked questions
Why does nvidia-smi hang for exactly 60 seconds?
The driver waits for VBIOS initialization and times out when ACPI or ROM access fails.
Does Proxmox 9.1 break Maxwell passthrough?
Not directly, but newer kernels combined with recent NVIDIA drivers can expose validation differences.
Is ACPI SSDT injection still required?
On many Optimus laptops, yes. Modern drivers may still reject the _ROM method if it does not fully emulate firmware behavior.
Can Maxwell mobile GPUs be reliably passed through?
Results vary a lot by laptop model and BIOS support, and many systems lack true discrete GPU isolation.
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