Hi Guestavo,
2016년 03월 24일 23:39에 Gustavo Padovan 이(가) 쓴 글:
Hi Inki,
2016-03-24 Inki Dae inki.dae@samsung.com:
Hi,
2016년 03월 24일 03:47에 Gustavo Padovan 이(가) 쓴 글:
From: Gustavo Padovan gustavo.padovan@collabora.co.uk
Hi,
This is a first proposal to discuss the addition of in-fences support to DRM. It adds a new struct to fence.c to abstract the use of sync_file in DRM drivers. The new struct fence_collection contains a array with all fences that a atomic commit needs to wait on
As I mentioned already like below, http://www.spinics.net/lists/dri-devel/msg103225.html
I don't see why Android specific thing is tried to propagate to Linux DRM. In Linux mainline, it has already implicit sync interfaces for DMA devices called dma fence which forces registering a fence obejct to DMABUF through a reservation obejct when a dmabuf object is created. However, Android sync driver creates a new file for a sync object and this would have different point of view.
Is there anyone who can explan why Android specific thing is tried to spread into Linux DRM? Was there any consensus to use Android sync driver - which uses explicit sync interfaces - as Linux standard?
Because we want explicit fencing as the Linux standard in the future to be able to do smart scheduling, e.g., send async jobs to the gpu and at the same time send async atomic commits with sync_file fd attached so they can wait the GPU to finish and we don't block in userspace anymore, quite similar to what Android does.
GPU is also DMA device so I think the synchonization should be handled transparent to user-space. And I know that Chromium guy already did similar thing with non-atomic commit only using implicit sync, https://chromium.googlesource.com/chromiumos/third_party/kernel branch name : chromeos-3.14
Of course, this approach uses a new helper framework placed in drm directory so I think if this framework can be moved into dma-buf directory after some cleanup and refactoring them if necessary. Anyway, I'm not sure I understood the smart scheduling you mentioned but I think we could do what you try to do without the explicit fence.
This would still use dma-buf fences in the driver level, but it has a lot more advantages than implicit fencing.
You means things for rendering pipeline debugging and merging sync fences?
Thanks, Inki Dae
Gustavo