Discussion Topic: Imagination GPU Drivers

[Carl Perry]

Something I wanted to discuss with this group is Imagination GPU Drivers. For many of us, we just need build machines and GPU doesn't really matter, but for others it does and being stuck with the BSP Operating System for these boards may not be a good fit. I talked with folks from StarFive and Alibaba/T-Head at summit about this issue, but I also learned a lot since then.

Right now it looks like every SoC from StarFive, T-Head, and Sophgo are using (and going to continue to use) Imagination GPU IP, specifically from the IMG series which according to the Kernel Driver documentation  (https://gitlab.freedesktop.org/frankbinns/powervr/-/blob/powervr-next/drivers/gpu/drm/imagination/Kconfig?ref_type=heads) "should" be supported by their Open Source Driver efforts: https://developer.imaginationtech.com/open-source-gpu-driver/

The reality is...not that. The number of firmware blobs available is very small and not for the GPUs in use for any of the RISC-V based boards. Now it's possible I've fallen into the trap of reading Marketing Text as anything more than Marketing. But I'm also wondering if anyone has any insights as to what support Imagination needs to expand their drivers to support these boards.

If this is not possible, the idea I talked with Alibaba and StarFive at summit about was to instead move their binary driver to DKMS to allow for distribution of that driver much like how the binary nvidia driver works. That way it can be used in other distros (mainline Debian, Fedora, Rocky, etc) more easily.

I'd love to hear everyone's thoughts or any leads on who to reach out to in order to try and make this situation better. Thanks everyone!

  -Carl

[Heinrich Schuchardt]

Imagination has upstreamed 4 GPUs to MESA and with Linux v6.7 as DRM
drivers to the kernel. But this effort did not include the Imagination
BXE-4-32 GPU which is used for instance in the JH7110 SoC.

My hope is that Imagination will continue on this path and enable
further GPUs.

I would assume that it is not up to Alibaba and StarFive but to
Imagination to allow the distribution of binaries that are their
intellectual property.

Distros generally don't want DKMS drivers and Linux has started to
enforce GPL checks in the API. To see some of the fun with DKMS have a
look at https://github.com/openzfs/zfs/pull/15767.

Fortunately Nvidia starts moving into the right direction (cf.
https://www.phoronix.com/review/nvidia-open-kernel).

Best regards

Heinrich

[Jason Kridner]

There is some amount of progress in supporting an upstream Mesa. BeagleV-Ahead (Alibaba TH1520-based) has an IMG BXM-4-64. This now has a Vulkan 1.0 (non-conformant) driver in mainline Mesa (https://docs.mesa3d.org/drivers/powervr.html).

Per https://lkml.org/lkml/2024/10/16/1507 -> https://gitlab.freedesktop.org/imagination/linux-firmware/-/issues/1, "TH1520 is a RISC-V SoC equipped with BXM-4-64 (BVNC 36.52.104.182) MC1 GPU" which is not 36.53.104.796, but we need to explore the compatibilities.