I suffered from the same bug too, but I think the solution is such that: when we switch to igpu mode, original libglx.so must be restored too. At least I understood it this way after inspecting "switchlibglx" script from original amd driver installator.
Thus the bug occured only in dpkg alternatives file "/var/lib/dpkg/alternatives/glx".Thus i propose such patch: diff -ruPN a/var/lib/dpkg/alternatives/glx b/var/lib/dpkg/alternatives/glx --- a/var/lib/dpkg/alternatives/glx 2014-05-04 12:26:36.000000000 +0400 +++ b/var/lib/dpkg/alternatives/glx 2014-05-04 15:15:00.258850761 +0400 @@ -24,7 +24,7 @@ /usr/lib/fglrx/fglrx_drv.so /usr/lib/mesa-diverted/i386-linux-gnu/libGL.so.1 /usr/lib/mesa-diverted/x86_64-linux-gnu/libGL.so.1 -/usr/lib/fglrx/fglrx-libglx.so + /usr/lib/mesa-diverted 5 After that igpu mode seems to be working properly (at least as far as I can say).
diff -ruPN a/var/lib/dpkg/alternatives/glx b/var/lib/dpkg/alternatives/glx --- a/var/lib/dpkg/alternatives/glx 2014-05-04 12:26:36.000000000 +0400 +++ b/var/lib/dpkg/alternatives/glx 2014-05-04 15:15:00.258850761 +0400 @@ -24,7 +24,7 @@ /usr/lib/fglrx/fglrx_drv.so /usr/lib/mesa-diverted/i386-linux-gnu/libGL.so.1 /usr/lib/mesa-diverted/x86_64-linux-gnu/libGL.so.1 -/usr/lib/fglrx/fglrx-libglx.so + /usr/lib/mesa-diverted 5
