Going back months have been patches for implementing GLX_MESA_query_renderer for all drivers within Mesa/Gallium3D, but the work wasn't mainlined yet. On Thursday by Emil Velikov we finally have a revised set of 19 patches for implementing GLX_MESA_query_renderer for all drivers per the Mesa mailing list.
This GLX_MESA_query_renderer support covers literally all drivers from the Intel "ILO" Gallium3D to Freedreno and Nouveau to the new VC4 Gallium3D driver. Let's hope that these patches will make it into Mesa 10.3 and that Linux game developers will begin optionally supporting this extension for querying driver/hardware information. There's also the open matter whether the proprietary NVIDIA and AMD drivers will also implement this GLX extension.