gr-fosphor: n00b run-time errors with benchmark tool and sink block on AMD APU

usual places. I have carefully followed the instructions at http://sdr.osmocom.org/trac/wiki/fosphor For building the benchmark tool, I replaced the line make LDFLAGS=-L/opt/intel/opencl-1.2-4.5.0.8/lib64 with make LDFLAGS=-L/opt/AMDAPPSDK-3.0/lib/x86_64/sdk for my AMD APU (CPU w/on-chip GPU) hardware and edited the Makefile to remove "-Werror" from the CFLAGS as otherwise the warning about cl_create_command_queue being deprecated causes Make to give up. After thus building the benchmark tool, running main yields libEGL warning: DRI2: failed to authenticate [+] Selected device: Devastator libGL error: No matching fbConfigs or visuals found libGL error: failed to load driver: swrast X Error of failed request: BadMatch (invalid parameter attributes) Major opcode of failed request: 157 (GLX) Minor opcode of failed request: 5 (X_GLXMakeCurrent) Serial number of failed request: 30 Current serial number in output stream: 30C Attempting to use the GRC fosphor sink block in a trivial flowgraph (with a signal source, noise source and add operation, intended to give me a tone with a noise floor), I get no output until I manually terminate it, and then in the GRC message pane I see libEGL warning: DRI2: failed to find _glapi_get_proc_address [+] Selected device: Devastator [!] CL Error (-34, /home/stu/gr-fosphor/lib/fosphor/cl.c:464): Unable to share waterfall texture into OpenCL context The same flowgraph, with the fosphor sink replaced by a QT GUI waterfall sink, works as expected. Any pointers would be greatly appreciated. -- Stu Card <stu.card(a)axenterprize.com>