Messages in this thread | | | Subject | Re: [git pull] habanalabs pull request for kernel 5.15 | From | Jeffrey Hugo <> | Date | Tue, 24 Aug 2021 19:16:59 -0600 |
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On 8/19/2021 12:48 PM, Dave Airlie wrote: > On Fri, 20 Aug 2021 at 03:07, Greg KH <gregkh@linuxfoundation.org> wrote: >> >> On Thu, Aug 19, 2021 at 02:02:09PM +0300, Oded Gabbay wrote: >>> Hi Greg, >>> >>> This is habanalabs pull request for the merge window of kernel 5.15. >>> The commits divide roughly 50/50 between adding new features, such >>> as peer-to-peer support with DMA-BUF or signaling from within a graph, >>> and fixing various bugs, small improvements, etc. >> >> Pulled and pushed out, thanks! > > NAK for adding dma-buf or p2p support to this driver in the upstream > kernel. There needs to be a hard line between > "I-can't-believe-its-not-a-drm-driver" drivers which bypass our > userspace requirements, and I consider this the line. > > This driver was merged into misc on the grounds it wasn't really a > drm/gpu driver and so didn't have to accept our userspace rules. > > Adding dma-buf/p2p support to this driver is showing it really fits > the gpu driver model and should be under the drivers/gpu rules since > what are most GPUs except accelerators.
Care to elaborate? I'm not trying to be cute, but all I see here is that dma-buf/p2p using drivers must be in drivers/gpu, yet many drivers outside of the gpu area use those features. Surely your position can't be that only drivers/gpu can use dma-buf or p2p (which is part of the PCIe spec).
> We are opening a major can of worms (some would say merging habanalabs > driver opened it), but this places us in the situation that if a GPU > vendor just claims their hw is a "vector" accelerator they can use > Greg to bypass all the work that been done to ensure we have > maintainability long term. I don't want drivers in the tree using > dma-buf to interact with other drivers when we don't have access to a > userspace project to validate the kernel driver assumptions.
Umm, isn't that [1]? The Habana device has the most open userspace I'm aware of. Seems disingenuous to claim you don't have access to a userspace project for this driver.
[1] - https://github.com/HabanaAI/hl-thunk
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