On Fri, Jul 13, 2012 at 4:44 PM, Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxx> wrote: > Hey, > > Op 13-07-12 20:52, Rob Clark schreef: >> On Fri, Jul 13, 2012 at 12:35 PM, Tom Cooksey <tom.cooksey@xxxxxxx> wrote: >>> My other thought is around atomicity. Could this be extended to >>> (safely) allow for hardware devices which might want to access >>> multiple buffers simultaneously? I think it probably can with >>> some tweaks to the interface? An atomic function which does >>> something like "give me all the fences for all these buffers >>> and add this fence to each instead/as-well-as"? >> fwiw, what I'm leaning towards right now is combining dma-fence w/ >> Maarten's idea of dma-buf-mgr (not sure if you saw his patches?). And >> let dmabufmgr handle the multi-buffer reservation stuff. And possibly >> the read vs write access, although this I'm not 100% sure on... the >> other option being the concept of read vs write (or >> exclusive/non-exclusive) fences. > Agreed, dmabufmgr is meant for reserving multiple buffers without deadlocks. > The underlying mechanism for synchronization can be dma-fences, it wouldn't > really change dmabufmgr much. >> In the current state, the fence is quite simple, and doesn't care >> *what* it is fencing, which seems advantageous when you get into >> trying to deal with combinations of devices sharing buffers, some of >> whom can do hw sync, and some who can't. So having a bit of >> partitioning from the code dealing w/ sequencing who can access the >> buffers when and for what purpose seems like it might not be a bad >> idea. Although I'm still working through the different alternatives. >> > Yeah, I managed to get nouveau hooked up with generating irqs on > completion today using an invalid command. It's also no longer a > performance regression, so software syncing is no longer a problem > for nouveau. i915 already generates irqs and r600 presumably too. > > Monday I'll take a better look at your patch, end of day now. :) let me send you a slightly updated version.. I fixed locally some locking fail in attach_fence() and get_fence() that I managed to introduce when converting from global spinlock to using the waitqueue's spinlock. BR, -R > ~Maarten > -- > To unsubscribe from this list: send the line "unsubscribe linux-media" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
