On Fri, Aug 26, 2016 at 04:29:57PM +0100, John Harrison wrote: > On 26/08/2016 16:08, John Harrison wrote: > >On 25/08/2016 10:08, Chris Wilson wrote: > >>Now that the user can opt-out of implicit fencing, we need to give them > >>back control over the fencing. We employ sync_file to wrap our > >>drm_i915_gem_request and provide an fd that userspace can merge with > >>other sync_file fds and pass back to the kernel to wait upon before > >>future execution. > It is worth mentioning in the description that this isn't just > useful for pushing the synchronisation down to user land. It also > allows synchronisation with non-rendering operations. But we already cover that in dma-buf. This is only useful for explicit synchronisation outside of the kernel, since we are trying to get everybody inside talking dma-buf. Software controlled fences are a no-go due to resitance from devs not wanting userspace being able to arbitrary hang the kernel. From that perspective, the only source of a fence is from the kernel. And the only desire to use explicit fencing is because implicit may be too coarse, or too accurate depending on your pov ;-) -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
