Is it possible to change PCIe BAR size on enviroment does not support Resizable-BAR

Hi, I’m implementing RDMA on Linux enviroment and I want to expand BAR size for incleasing mapping memory size are using on RDMA.

My enviroment is bellow.

item content
OS Ubuntu 22.04.04 (Linux version : 5.15.0-119-generic )
GPU RTX A5000
M/B SuperMicro X12DAi-N6
CPU Intel(R) Xeon(R) Gold 6326 CPU @ 2.90GHz
# lspci | grep -i nvi
4b:00.0 VGA compatible controller: NVIDIA Corporation GA102GL [RTX A5000] (rev a1)
4b:00.1 Audio device: NVIDIA Corporation GA102 High Definition Audio Controller (rev a1)
# lspci -vvvs 4b:00.0
...
        Capabilities: [bb0 v1] Physical Resizable BAR
                BAR 0: current size: 16MB, supported: 16MB
                BAR 1: current size: 256MB, supported: 64MB 128MB 256MB 512MB 1GB 2GB 4GB 8GB 16GB 32GB
                BAR 3: current size: 32MB, supported: 32MB

I found some approach to change BAR sizes.

However, this method can probably only be used in environments where Resizable-BAR is enabled, and *_resize is not found in my environment.

I found my enviroment is not support Resizable-map https://www.supermicro.com/support/faqs/faq.cfm?faq=35231

I understand as Resizable-BAR is “dynamic” changing BAR size which lookable from CPU.

My question is “Is it possible to change this BAR size? (static is ok)”

It depend on CPU and PCIE bridge hw design.

I solved this program by using NVIDIA Display Mode Selector Tool | NVIDIA Developer

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.