This test page: https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/conformance-suites/1.0.1/webgl-conformance-tests.html gives this error: failed: getError expected: NO_ERROR. Was INVALID_OPERATION : drawing with a valid program shouldn't generate a GL error on at least 2 different systems: Mesa 7.11 + r600g Mac+NVIDIA
Ergh, ok, this is a driver bug. Interesting that these two very different drivers share it. Problem doesn't occur on our Windows and Linux test slaves using NVIDIA.