On Wed, May 07, 2014 at 11:19:57AM +0530, Akash Goel wrote: > On Mon, 2014-05-05 at 16:07 +0200, Daniel Vetter wrote: > > On Mon, May 05, 2014 at 05:13:18PM +0530, akash.goel@xxxxxxxxx wrote: > > > From: Akash Goel <akash.goel@xxxxxxxxx> > > > > > > There is a use case, when user space (display compositor) tries > > > to directly flip a fb (without any prior rendering) on primary > > > plane. So the backing pages of the object are allocated at page > > > flip time only, which takes time. Since, this buffer is supposed to > > > serve as a blanking buffer (black colored), we can setup all the GTT entries > > > of that blanking buffer with scratch page (which is already zeroed out). > > > This saves the time in allocation of real backing physical space for the > > > blanking buffer and flushing of CPU cache. > > > > > > Signed-off-by: Akash Goel <akash.goel@xxxxxxxxx> > > > > That sounds very much like a special case of the fallocate ioctl where we > > simply allocat 0 real backing storage pages. > > -Daniel > > > > Hi Daniel, > > Yes no real backing storage is needed, but still the object should be > allowed to get mapped into the GGTT, using the scratch page (already > zeroed out). > > Is there a patch for a new drm/i915 ioctl similar to fallocate, which > could be used here? Geez, you guys shouldn't just dump patches onto intel-gfx but read a bit what other people are doing. Especially when they work for the same team ;-) http://comments.gmane.org/gmane.comp.freedesktop.xorg.drivers.intel/36351 Cheers, Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
