[Mesa-dev] vbo code and flush explicit mapping

[Dave Airlie]

I've been playing with a gallium driver, and started looking at some
wierd gears behaviour,

The vbo code maps the buffer with GL_MAP_FLUSH_EXPLICIT_BIT which to
me requires that at some point
we call ctx->Driver.FlushMappedBufferRange. Now the code attempts to
call it in vbo_exec_vtx_unmap
but from what I can see the length is always 0 in there and so we
never get called.

GLsizeiptr length = (exec->vtx.buffer_ptr - exec->vtx.buffer_map) *
sizeof(float);

but I can not see buffer_ptr != buffer_map when we hit this code, I'm
a bit lost at this point, maybe someone else might know more.

Dave.