On 27/06/16 18:12, Ilia Mirkin wrote: > On Mon, Jun 27, 2016 at 6:36 AM, Alejandro Piñeiro <apinhe...@igalia.com> > wrote: >> >> On 27/06/16 12:33, Alejandro Piñeiro wrote: >>> On 27/06/16 03:08, Grazvydas Ignotas wrote: >>>> On Sat, Jun 25, 2016 at 4:54 PM, Alejandro Piñeiro <apinhe...@igalia.com> >>>> wrote: >>>>> In theory they don't overdrawn. The test has a square formed by N >>>>> non-overlapping triangles. With just one call to glDrawRangeElements, >>>>> this always works. But if we split it in M subsets, so M calls to >>>>> glDrawRangeElements with N/M triangles per call, with low resolutions >>>>> and a high amount of triangles, some texels start to fail. And not >>>>> always the same amount of texels (so as you mentioned, undefined >>>>> territory). Although it is a guess, I assume that is cause for artifacts >>>>> on the triangle borders when drawing with so low resolution. >>>> Perhaps this is somehow related to this bug: >>>> https://bugs.freedesktop.org/show_bug.cgi?id=96624 >>>> There a texture problem shows up after one of glDrawRangeElements >>>> calls with a lot of primitives. >>> Not sure if they are related. Note that the issue I mention gets fully >>> solved with glTextureBarrier and additionally, it happens on haswell too. >>> >>> In any case, reading that bug gave me an idea. I have been toying with >>> MESA_DEBUG=flush (that until your email I didn't know that exists). >>> Looking at the code, it adds the equivalent to a glFlush after each >>> drawing call. Using it gets the test (all 48 subtests) passing. So right >>> now Im more biased to think that is an issue on glTextureBarrier. >> Another hint towards being an issue on glTextureBarrier implementation: >> if instead of using MESA_DEBUG=flush, I replace glTextureBarrier for >> glFlush on the original test (so one full flush after all the square, >> but not after each drawing call) all the subtests keep passing too. > I flipped ARB_texture_barrier on for i965 based on comments that > others made about how the hw worked. I don't think anyone was *too* > sure that it was correct, but the tests (at the time) passed, so I > don't think anyone gave it much more thought. Commit 71e187430c, ftr.
Yes, I already found that one while researching. I found more interesting the annotate section when you sent the patch: https://lists.freedesktop.org/archives/mesa-dev/2015-August/091632.html On that section you mention that the test passes even without the flush. FWIW, with the new detailed test I sent last week to the mailing list, if the glTextureBarrier call on the test is removed, it goes from 5-6 failed subtest to 12 failed subtests (out of 48). So I think that that patch was a step in the correct direction. FWIW2, if I replace the call to brw_emit_mi_flush with a call to intel_batchbuffer_flush all the subtests passes correctly, but probably that is an overkill. Before suggesting that change, I will check if it is possible to solve it on the call of brw_emit_mi_flush. BTW, this is a way to say that I NAK my own piglit patch. At this moment I think that it is something to be solved on the mesa side. BR _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
