[Mesa-dev] [PATCH 5/6] st/mesa: disable EXT_separate_shader_objects

[Marek Olšák]

The extension disallows elimination of set-but-unused varyings.
---
 docs/relnotes/9.2.html                 |    3 +++
 src/mesa/state_tracker/st_extensions.c |    9 ++++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/docs/relnotes/9.2.html b/docs/relnotes/9.2.html
index 0dcc960..99f6374 100644
--- a/docs/relnotes/9.2.html
+++ b/docs/relnotes/9.2.html
@@ -63,6 +63,9 @@ Note: some of the new features are only available with certain drivers.
 
 <ul>
 <li>Removed d3d1x state tracker (unused, unmaintained and broken)</li>
+<li>GL_EXT_separate_shader_objects has been removed from all Gallium drivers,
+    because it disallows critical GLSL shader optimizations.
+    GL_ARB_separate_shader_objects doesn't have this issue.
 </ul>
 
 </div>
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index 966722c..43111d6 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -559,7 +559,14 @@ void st_init_extensions(struct st_context *st)
    ctx->Extensions.EXT_point_parameters = GL_TRUE;
    ctx->Extensions.EXT_provoking_vertex = GL_TRUE;
    ctx->Extensions.EXT_secondary_color = GL_TRUE;
-   ctx->Extensions.EXT_separate_shader_objects = GL_TRUE;
+
+   /* IMPORTANT:
+    *    Don't enable EXT_separate_shader_objects. It disallows certain
+    *    optimizations in the GLSL compiler and therefore is considered
+    *    harmful.
+    */
+   ctx->Extensions.EXT_separate_shader_objects = GL_FALSE;
+
    ctx->Extensions.EXT_texture_env_dot3 = GL_TRUE;
    ctx->Extensions.EXT_vertex_array_bgra = GL_TRUE;
 
-- 
1.7.10.4