On Tue, Jul 22, 2014 at 4:39 PM, Christian König <christian.koenig@xxxxxxx> wrote: > Am 22.07.2014 16:27, schrieb Maarten Lankhorst: > >> op 22-07-14 16:24, Christian König schreef: >>>> >>>> No, you really shouldn't be doing much in the check anyway, it's meant >>>> to be a lightweight check. If you're not ready yet because of a lockup >>>> simply return not signaled yet. >>> >>> It's not only the lockup case from radeon I have in mind here. For >>> userspace queues it might be necessary to call copy_from_user to figure out >>> if a fence is signaled or not. >>> >>> Returning false all the time is probably not a good idea either. >> >> Having userspace implement a fence sounds like an awful idea, why would >> you want to do that? > > > Marketing moves in mysterious ways. Don't ask me, but that the direction it > currently moves with userspace queues and IOMMU etc... Fence-based syncing between userspace queues submitted stuff through doorbells and anything submitted by the general simply wont work. Which is why I think the doorbell is a stupid interface since I just don't see cameras and v4l devices implementing all that complexity to get a pure userspace side sync solution. But that's a different problem really, and I guess marketing will eventually figure this one out, too. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
