libdrm_amdgpu being forked and merged into Mesa
Michel Dänzer
michel.daenzer at mailbox.org
Fri Oct 25 14:36:18 UTC 2024
On 2024-10-25 12:18, Bas Nieuwenhuizen wrote:
> On Fri, Oct 25, 2024 at 11:21 AM Michel Dänzer <michel.daenzer at mailbox.org <mailto:michel.daenzer at mailbox.org>> wrote:
>
> On 2024-10-24 17:08, Marek Olšák wrote:
> > We don't need to share the same VMID between ROCm and Mesa. We don't
> > need to share the same driver FD between ROCm and Mesa either. It will
> > be like having 2 different processes, and that should always work.
>
> Per https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31756#note_2626236 <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31756#note_2626236>, does anything prevent the application from passing the same DRM file description (doesn't need to be the same *descriptor*) to separate drivers? (Not sure it can even pass a DRM fd to ROCm, surely can e.g. to radeonsi & AMDVLK though)
>
>
> In RADV the app has no way to pass in a drm fd, there is only a way to query the major/minor from the fd (https://registry.khronos.org/vulkan/specs/1.3-extensions/html/chap55.html#VK_EXT_physical_device_drm <https://registry.khronos.org/vulkan/specs/1.3-extensions/html/chap55.html#VK_EXT_physical_device_drm>).
Hmm. So Wayland compositors which use Vulkan have to share BOs from Vulkan into their DRM file description for KMS via dma-buf?
How about ROCm, no way to pass in / retrieve a DRM file descriptor there either?
> (not to mention that it would mean that any users would need to use libdrm_amdgpu. Given that the most likely combination of GBM with shared fd/handle stuff is kernel modesetting and nobody uses libdrm_amdgpu with that, having a shared libdrm_amdgpu would not help there)
Not sure what you mean here, Wayland compositors use radeonsi with KMS.
--
Earthling Michel Dänzer \ GNOME / Xwayland / Mesa developer
https://redhat.com \ Libre software enthusiast
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