https://bugs.freedesktop.org/show_bug.cgi?id=103915
--- Comment #1 from fin4478@hotmail.com --- You are using really old kernel with latest Mesa code and old Debian and that can cause problems. Use Debian testing Xfce and a custom kernel from kernel.org or from https://cgit.freedesktop.org/~agd5f/linux
Also use Mesa dev, you can use Oipaf ppa Artful version with Debian testing. https://launchpad.net/~oibaf/+archive/ubuntu/graphics-drivers http://www.webupd8.org/2014/10/how-to-add-launchpad-ppas-in-debian-via.html