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. The "old" OpenGL renderer, "gl", does not seem to suffer from this - but it is no longer the default, has been deleted in newer upstream versions, and crashes in two (unrelated) tests on mipsel, so I'm going to disable testing for "gl" in the next upload to avoid wasting machine resources and developer time on it. I'm going to skip these two tests on mips*el. I don't know what practical effect this will have on GTK applications; I would recommend that people who are interested in GUIs on mips*el should try the gtk-4-examples package when mips*el builds become available, and find out. smcv
Simon McVittie <smcv@debian.org> 于2021年9月3日周五 上午7:21写道： Thank you. We will dig it. We (CIP United) are taking care about MIPS ecosystem, and feel free to contact use for any MIPS problems.
but no other release architecture?
With GTK 4.6.6+ds-2, there are additional test failures: see
<https://buildd.debian.org/status/fetch.php?pkg=gtk4&arch=mips64el&ver=4.6.6%2Bds-2&stamp=1660047438&raw=0>.
I suspect these were triggered by an upgrade in some other package
(perhaps mesa or llvm-toolchain-14?) rather than GTK, because the GTK
rendering code did not change between 4.6.6+ds-1 and 4.6.6+ds-2.
From the failing reftests' output (available uuencoded in the build log,
and attached in decoded form for your convenience) we can see that the
failures follow a similar pattern: there is a repeating pattern of pixels
with the wrong value.
smcv
Control: reassign -1 src:mesa
Control: affects -1 + src:gtk4
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