Package: openscad Severity: important Tags: upstream as can be seen in #848895 and is being reported in an increasingly large number of other packages that use x11 and opengl, there is an obscure race-condition which is causing intermittent "hanging" of all and any packagees that make significant use of x11 / opengl.
the issue appears to be that a race condition causes a frame to be dropped. however once there is only one frame dropped, *all* subsequent frames stop from that point onwards. the "recovery" method on chromium is to kill the errant process, but that's only because a background thread takes care of drawing the contents of a tab (which can subsequently be "refreshed"). in the case of most applications which are single-process, the "recovery" method is to press ctrl-alt-f1 then ctrl-alt-f7 which is an extremely bizarre way to break the deadlock that is 100% guaranteed to work. several people have reported totally different GPUs so it is known not to be a specific GPU-related issue. several people have reported using totally different window managers so it is known not to be a specific window-manager-related issue. however until the actual cause is known it's become necessary to alert *every* single affected package so that (eventually) the underlying cause can be tracked down, collaboratively. it also does not help that the exact dependency in which the root cause of the problem is simply... not known. the google chromium browser team have *attempted* to create workarounds for something like over a year, now, and each and every single workaround for the underlying race condition proves to have increasingly severe consequences, the most recent being unacceptably-high CPU load for several minutes across multiple threads, just before the race condition is triggered. so... sorry... complicated scenario! -- System Information: Debian Release: 7.4 APT prefers testing APT policy: (500, 'testing'), (500, 'stable') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 4.9.0-1-amd64 (SMP w/8 CPU cores) Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Versions of packages openscad depends on: pn libboost-filesystem1.55.0 <none> pn libboost-program-options1.55.0 <none> pn libboost-regex1.55.0 <none> pn libboost-system1.55.0 <none> pn libboost-thread1.55.0 <none> ii libc6 2.23-4 pn libcgal10 <none> ii libgcc1 1:6.3.0-10 ii libgl1-mesa-glx [libgl1] 13.0.2-3 ii libglew1.10 1.10.0-3 ii libglib2.0-0 2.50.1-1 ii libglu1-mesa [libglu1] 9.0.0-2.1 ii libgmp10 2:6.1.2+dfsg-1 ii libmpfr4 3.1.3-1 ii libopencsg1 1.3.2-2+b1 ii libqt4-opengl 4:4.8.6+git64-g5dc8b2b+dfsg-2+b1 ii libqtcore4 4:4.8.6+git64-g5dc8b2b+dfsg-2+b1 ii libqtgui4 4:4.8.6+git64-g5dc8b2b+dfsg-2+b1 ii libstdc++6 6.3.0-10 ii libx11-6 2:1.6.4-2 Versions of packages openscad recommends: pn openscad-mcad <none> Versions of packages openscad suggests: pn geomview <none> ii librecad 2.0.4-1 ii meshlab 1.3.2+dfsg1-2+b1 pn openscad-testing <none>
