nvgrace_gpu_open_device() sets up the fake BAR registers and remap_lock only when usemem.memlength is nonzero. The check exists for fallback mode, which used to share this open path. Fallback mode now has its own open_device, so only devices with ACPI memory properties reach this one. For those devices usemem.memlength is never zero: an empty region from nvgrace_gpu_fetch_memory_property() selects fallback mode, and probe fails when nvgrace_gpu_init_nvdev_struct() rounds usemem down to nothing. Do the setup unconditionally. Assisted-by: LLM Signed-off-by: Andrea Parri <parri.andrea@gmail.com> Reviewed-by: Ankit Agrawal <ankita@nvidia.com> Link: https://lore.kernel.org/r/20261015081937.405320-3-parri.andrea@gmail.com Signed-off-by: Alex Williamson <alex@shazbot.org>