Created attachment 122892 [details]
Program which test for the issue
When mesa git fa46848e51a619aba5a748316fe8fe4c2e17d243 is built against LLVM 3.8.0, with a Radeon R9 270, support for the GL_ARB_shader_storage_buffer_object extension is claimed. However, GL_MAX_COMBINED_SHADER_STORAGE_BLOCKS is 0. The minimum required by the ARB_shader_storage_buffer_object specification is 8.
https://cgit.freedesktop.org/mesa/mesa/commit/?id=bfd11c599600960f966d5d217b8dc20442108ef1 makes it look as if support was only intended for LLVM 3.9 or later.
Hi James, thanks for the report. Probably some confusion in how the statetracker maps Gallium cap bits to extension support, I'm going to take a look.
https://patchwork.freedesktop.org/patch/80793/ should fix this.
Should be fixed in Mesa master, commit 9e9a2bb44aa7b317919793f2320bd995ff373bbb
Confirmed. Thanks for the quick fix.