[PATCH v6 10/14] drm/panthor: Add the scheduler logical block

[Simona Vetter]

On Thu, Feb 29, 2024 at 05:22:24PM +0100, Boris Brezillon wrote:
> - Add our job fence as DMA_RESV_USAGE_WRITE to all external objects
>   (was previously DMA_RESV_USAGE_BOOKKEEP). I don't get why, given
>   we're supposed to be fully-explicit, but other drivers do that, so
>   there must be a good reason

Just spotted this: They're wrong, or they're userspace is broken and
doesn't use the dma_buf fence import/export ioctl in all the right places.
For gl this simplifies things (but setting write fences when you're only
reading is still bad, and setting fences on buffers you don't even touch
is worse), for vulkan this is just bad.

I think you want a context creation flag for userspace that's not broken,
which goes back to USAGE_BOOKKEEP for everything.
-Sima
-- 
Simona Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch