On Wed, Oct 31, 2012 at 04:26:54PM +0100, Daniel Vetter wrote: > On Wed, Oct 31, 2012 at 4:23 PM, Jesse Barnes <jbarnes at virtuousgeek.org> 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. > > How are we gonna sync up with outstanding rendering before issuing the > flip? If the answer is involves enabling the render irq, I'm not gonna > like it ;-) That's currently the only major TODO item on my list. Currently the ioctl just ends up blocking when I pin the buffers, but I need some async method to avoid that. So yes, irqs seem like the right approach here. What's the problem w/ irqs? -- Ville Syrj?l? Intel OTC
