Question on UAPI for fences

[Daniel Vetter]

On Fri, Sep 12, 2014 at 03:23:22PM +0200, Christian König wrote:
> Hello everyone,
>
> to allow concurrent buffer access by different engines beyond the multiple
> readers/single writer model that we currently use in radeon and other
> drivers we need some kind of synchonization object exposed to userspace.
>
> My initial patch set for this used (or rather abused) zero sized GEM buffers
> as fence handles. This is obviously isn't the best way of doing this (to
> much overhead, rather ugly etc...), Jerome commented on this accordingly.
>
> So what should a driver expose instead? Android sync points? Something else?

I think actually exposing the struct fence objects as a fd, using android
syncpts (or at least something compatible to it) is the way to go. Problem
is that it's super-hard to get the android guys out of hiding for this :(

Adding a bunch of people in the hopes that something sticks.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch