reassign 754894 src:qtbase-opensource-src 5.2.0+dfsg-1 severity 754894 important thanks
On Tuesday 15 July 2014 19:48:06 Boris Barbulovski wrote: > Package: libqt5core5a (actually all qt5 libraries) > Version: 5.3.1+dfsg-3(jessie) > > >From Qt 5.3 SSE2 is enabled by default crashing every Qt app when run > > on i386 version with older(non SSE2) processor. > > > Solution: Disable SSE2 when building Qt5 packages for i386. Not quite. > I will paste paragraph from Phoronix article regarding this issue: > > *- Qt 5.3 by default for 32-built builds now depends upon SSE2 CPU support. > SSE2 CPUs have been around for the past decade and building code > optimized for SSE2+ will yield better performance. SSE2 has been found > since Intel Pentium 4 CPUs and for AMD hardware since the Opteron / > Athlon 64 debut. Those building Qt 5.3 i386 binaries wishing to support > ancient CPUs can pass -no-sse2 to still maintain pre-SSE2 compatibility.* > > here is the article > <http://www.phoronix.com/scan.php?page=news_item&px=MTY3MDU>. Please use good data sources: upstream. There is a better fix pending someone to step up for doing the job. It's not that simple as "just disable SSE2" because that would render some parts simply unusable. The correct fix is to build *some* of the libs twice: one with SSE2 support and one without it. If properly installed the linker will do the correct job at runtime. Interestingly enough, so far no one has reproduced this bug so far. Can you reproduce it? It would be good to know so you can tests the packages for us. Kinds regards, Lisandro. -- Lisandro Damián Nicanor Pérez Meyer http://perezmeyer.com.ar/ http://perezmeyer.blogspot.com/
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