On Tue, Mar 04, 2014 at 05:06:22PM +0200, Ville Syrjälä wrote: > On Tue, Mar 04, 2014 at 10:38:58PM +0800, Chia-I Wu wrote: > > On Tue, Mar 4, 2014 at 5:41 PM, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote: > > > This reverts commit 116f2b6da868dec7539103574d0421cd6221e931. > > > > > > This optimization causes widespread corruption in games, and even in > > > glxgears, on my ivb:gt1. The corruption appears like z-fighting of > > > overlapping polygons in the HiZ buffer. > > > > > > The observation ties in very closely with the description of the > > > optimization disabled by default on IVB: > > > > > > "The Hierarchical Z RAW Stall Optimization allows non-overlapping > > > polygons in the same 8x4 pixel/sample area to be processed without > > > stalling waiting for the earlier ones to write to Hierarchical Z > > > buffer." > > > > > > No reason is given for why it is disabled by default, usually for such > > > optimizations it is that it is incomplete. However, there is no > > > indication whether this a gt1 only issue either. Before considering > > > reenabling this optimization, I would first suggest reproducing the > > > corruption in piglit. > > I wonder if Haswell GT1 is affected too (that's in another commit). I > > do not own a GT1 for either GEN to verify the issue or to create a > > sensible piglit test. > > I'm seeing corruption on IVB GT2 as well. I might be more blind than > Chris or it's less subtle on GT2 since it took me a while to spot it. > Seems to be easiest to spot in Epic citadel when you go inside the > temple. I can't spot the same corruption on HSW GT3. Queued for -next, thanks for the patch. We can tackle hsw when that on blows up ... -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
