On Mon, 2009-05-25 at 18:19 +0100, Dave Airlie wrote: > > > > > > I'd like to fix this at some point, but I never got to understand wtf the > > > blackbars were coming from, apart from it being something to do with > > > evicted buffers. > > > > Aha! > > > > So, two characteristics of the black bars I remember: > > > > - They were 16-pixel (64-byte) horizontal stripes, 64-byte aligned. > > That is, cache lines. > > - They were black. > > That is, the cache-line contents for a newly zeroed page > > > > Note also that the function to add pages to the page free lists - > > drm_add_pages_locked() - calls set_memory_wc(), but it doesn't do the > > other thing that drm_ttm_set_caching() does: call drm_clflush_pages() > > Ah that could have been it. care to give it a hack, I'm on hols for > another week or so.
Backing out the referenced change and adding a call to clflush_pages() seems to work in some quick testing, I'll see if any problems pop up in the next few days. If not, I'll throw it on my (modest sized) pile of mesa and kernel patches that I'm accumulating vs. the current F11 tree. Enjoy the rest of your vacation. - Owen [ Even with the change, there still is a noticeable performance win from dropping the size of the DMA buffer in mesa - binding the 1M buffers into AGP space takes a measurable amount of time. ] ------------------------------------------------------------------------------ Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT is a gathering of tech-side developers & brand creativity professionals. Meet the minds behind Google Creative Lab, Visual Complexity, Processing, & iPhoneDevCamp asthey present alongside digital heavyweights like Barbarian Group, R/GA, & Big Spaceship. http://www.creativitycat.com _______________________________________________ Mesa3d-dev mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
