[Linaro-mm-sig] [PATCH v5 00/40] drm/msm: sparse / "VM_BIND" support

[Dave Airlie]

On Tue, 20 May 2025 at 03:54, Rob Clark <robdclark at gmail.com> wrote:
>
> From: Rob Clark <robdclark at chromium.org>
>
> Conversion to DRM GPU VA Manager[1], and adding support for Vulkan Sparse
> Memory[2] in the form of:
>
> 1. A new VM_BIND submitqueue type for executing VM MSM_SUBMIT_BO_OP_MAP/
>    MAP_NULL/UNMAP commands
>
> 2. A new VM_BIND ioctl to allow submitting batches of one or more
>    MAP/MAP_NULL/UNMAP commands to a VM_BIND submitqueue
>
> I did not implement support for synchronous VM_BIND commands.  Since
> userspace could just immediately wait for the `SUBMIT` to complete, I don't
> think we need this extra complexity in the kernel.  Synchronous/immediate
> VM_BIND operations could be implemented with a 2nd VM_BIND submitqueue.

This seems suboptimal for Vulkan userspaces. non-sparse binds are all
synchronous, you are adding an extra ioctl to wait, or do you manage
these via a different mechanism?

Dave.