On Wed, 31 Oct 2012 14:53:24 +0200 Ville Syrj?l? <ville.syrjala at linux.intel.com> wrote: > On Tue, Oct 30, 2012 at 01:33:47PM -0500, Jesse Barnes wrote: > > The hw supports async flips through the render ring, so why not expose it? > > It gives us one more "tear me harder" option we can use in the DDX and > > for other cases where simply flipping to the latest buffer is more > > important than visual quality. > > The only reason I can see why anyone would really want async flips is > when you're restricted to double buffering. With triple buffering you > should be able to override the previous flip w/o tearing. > > Well, actually if you use the ring based flips, then you can't do the > override. My atomic page flip code can do it because it's using mmio > flips. There were also other reasons favoring mmio over ring. > > Once the atomic code is deemed ready, I would suggest we just nuke the > ring based flip code (pun intended). Yeah, I agree. In fact one of the first versions of the flip code used mmio, and I think it's a better way to go. I think you're correct about triple buffering, but I don't know if our DDX does the right thing here these days or not (by default). -- Jesse Barnes, Intel Open Source Technology Center
