This bug also affects jessie-backports beignet when used with jessie-backports Linux (which is likely as, for unrelated reasons, OpenCL doesn't work properly on Haswell with jessie Linux). Fixed backport in Alioth, ready for upload.
The upstream report of "this isn't a complete fix" turned out to be
mistaken: the user had both versions and had accidentally used the
unfixed one. https://bugs.freedesktop.org/show_bug.cgi?id=100639#c19
