[Mesa-dev] [PATCH 12/17] mesa/st: make sure the const buffer is large enough for packed uniforms

[Timothy Arceri]

---
 src/mesa/state_tracker/st_atom_constbuf.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/mesa/state_tracker/st_atom_constbuf.c b/src/mesa/state_tracker/st_atom_constbuf.c
index 7f17546..eb8f6b3 100644
--- a/src/mesa/state_tracker/st_atom_constbuf.c
+++ b/src/mesa/state_tracker/st_atom_constbuf.c
@@ -83,21 +83,27 @@ void st_upload_constants(struct st_context *st, struct gl_program *prog)
 
    /* Make all bindless samplers/images bound texture/image units resident in
     * the context.
     */
    st_make_bound_samplers_resident(st, prog);
    st_make_bound_images_resident(st, prog);
 
    /* update constants */
    if (params && params->NumParameters) {
       struct pipe_constant_buffer cb;
-      const uint paramBytes = params->NumParameters * sizeof(GLfloat) * 4;
+
+      /* We need to align to 4 as the driver will expect to load four values
+       * regardless of how many values the last param has. It's safe to do the
+       * align as the param list always allocates extra memory.
+       */
+      const uint paramBytes =
+         align((params->NumParameterValues * sizeof(GLfloat)) + 1, 4);
 
       /* Update the constants which come from fixed-function state, such as
        * transformation matrices, fog factors, etc.  The rest of the values in
        * the parameters list are explicitly set by the user with glUniform,
        * glProgramParameter(), etc.
        */
       if (params->StateFlags)
          _mesa_load_state_parameters(st->ctx, params);
 
       _mesa_shader_write_subroutine_indices(st->ctx, stage);
-- 
2.9.4