Thanks Dave, got your suggestion.

David Zhou

On 2016年12月02日 03:44, Dave Airlie wrote:
Hi David,

Some one major review suggestion, don't use file descriptors for
semaphore, as fd's are a limited resource and we don't want to use
them all up.

You create semaphore objects and use them in a single process without
them being fds, then when userspace wants to share with another
you convert the semaphore object to an fd, pass it to the other
process and have it convert it back into a semaphore object.


On 1 December 2016 at 16:11, zhoucm1 <> wrote:
Hi Dave,

As the attached, our Vulkan team is verifying it.

David Zhou

On 2016年12月01日 13:44, Dave Airlie wrote:

On 1 Dec. 2016 15:22, "zhoucm1" <> wrote:
Yes, the old implementation which is already in upstream libdrm is out of
data, there isn't other user, so we want to drop it when new semaphore is
verified OK.
Could you post some patches for the new one? Otherwise I'll have to write
one for radv.

David Zhou

On 2016年12月01日 10:36, Mao, David wrote:
Hi Dave,
i believe your first attempt is correct.
The export/import semaphore needs refine of the semaphore implementation.
We are working on that.

Best Regards,
On 1 Dec 2016, at 10:12 AM, Dave Airlie <> wrote:

Hey all,

So I've started adding semaphore support to radv but I'm not really
sure what the API to the semaphore code is.

the Vulkan API is you get a command submission of a number of submit
units which have a 0-n wait semaphore, 0-n command buffers and 0-n
signal semaphores.

Now I'm not sure how I should use the APIs with those.

My first attempt is

call amdgpu_cs_wait_semaphore on all the wait ones, call the cs submit
API, then call the amdgpu_cs_signal_semaphore on all the signal ones?

or should I be up front calling wait/signal then submitting the command

Also upcoming work requires possibly sharing semaphores between
processes, is there any indication how this might be made work with
the libdrm_amdgpu semaphore implementation?

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