Control: reassign -1 src:mesa Control: affects -1 + src:gtk4 On Fri, 03 Sep 2021 at 00:19:29 +0100, Simon McVittie wrote: > GTK 4 has a new scene-graph-based rendering model, "GSK", with an OpenGL > preferred implementation and a Cairo fallback. Its regression tests draw > various combinations of "render nodes" and check the results against > reference PNG images. > > When using the "new" OpenGL renderer, "ngl", there's a weird rendering > glitch on mips*el on two tests involving repeating a pattern: the top > left pixel in each 2x2 block is darker than the other three. > For more details and comparison images: > https://gitlab.gnome.org/GNOME/gtk/-/issues/4228 > > Is there anything unusual about the OpenGL implementation on mips*el > that would cause this sort of thing? It seems to be using Mesa swrast_dri.so > (which I think is llvmpipe?), the same as any other machine without a GPU.
This seems likely to be a mips*-specific bug in Mesa's llvmpipe or some dependency of llvmpipe (maybe LLVM?), rather than directly a GTK bug: I can avoid the test failure by running tests with GALLIUM_DRIVER=softpipe and LIBGL_ALWAYS_SOFTWARE=true in the environment. I've set up the GTK build to use GALLIUM_DRIVER=softpipe and LIBGL_ALWAYS_SOFTWARE=true for build-time tests, and I don't intend to investigate this further from GTK's point of view. Investigation by the mips porting team would be appreciated. smcv