On Fri, Mar 13, 2015 at 10:27:38AM +0100, Daniel Vetter wrote: > If supporting systems without full ppgtt is a requirement for you (still > wonky on gen8 a bit, so might be a good strategy) then imo it's the > PIN_BIAS idea I've laid out earlier in this thread. That one will work > everywhere. softpin can unexpectedly fail without full ppgtt if the kernel > decides to put something at a given spot, which imo means we should only > expose it on full ppgtt systems. > > And PIN_BIAS should be fairly easy to wire up since the internal logic is > all there already. So "just" needs an execbuf flag, igt test and > appropriate userspace to set that new bit.
It doesn't though. To provide the guarantee userspace is asking for (which is that address 0 goes to a special, preferrably inaccessible, page), you have to evict the first N pages in the GGTT. That is just as likely to fail with an execbuffer flag as it would with an execobject flag. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx
