On Thu, Sep 17, 2015 at 05:19:02PM +0300, ville.syrjala@xxxxxxxxxxxxxxx wrote: > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > On LLC platforms there's no need to use GTT mmap for unsynchronized > maps if the object isn't tiled. So switch to using CPU mmap for linar > objects. This avoids having to use the GTT for GL buffer objects > entirely, and thus we can ignore the GTT mappable size limitation. > For tiled objects we still want the hardware to do the (de)tiling so > keep using GTT for such objects. > > The display engine is not coherent even on LLC platforms, so this won't > work too well if we mix scanout and unsynchronized maps of linear bos. > Actually, that would only be a problem for an already uncached object, > otherwise it will get clflushed anyway when being made UC/WC prior to > scanout. The alreday UC object case could be handled by either > clflushing straight from userspace, or we could add a new ioctl to > clflush or mark the object as cache_dirty so that it will get > clflushed in the future just prior to scanout. I started to think > that a small nop pwrite would have the desired effect, but in fact it > would only flush the cachelines it touches so wouldn't actually work > I doubt we want to pwrite the entire object just to get it clflushed. > > This fixes Ilias's arb_texture_buffer_object-max-size piglit test > on LLC platforms. Note that there have been patches to fix mesa/i965 for this issue on both llc and !llc on the mailing list for a few months. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
