8 files changed, 28 insertions, 9 deletions
diff --git a/src/mesa/drivers/dri/common/drirc b/src/mesa/drivers/dri/common/drirc
index e1874c3f1dc..183a1dcabe8 100644
--- a/src/mesa/drivers/dri/common/drirc
+++ b/src/mesa/drivers/dri/common/drirc
@@ -37,26 +37,26 @@ TODO: document the other workarounds.
 
         <application name="Unigine Heaven (32-bit)" executable="heaven_x86">
             <option name="allow_glsl_extension_directive_midshader" value="true" />
-            <!-- remove disable_blend_func_extended if 4.1 ever comes out -->
-            <option name="disable_blend_func_extended" value="true" />
+            <!-- remove dual_color_blend_by_location if 4.1 ever comes out -->
+            <option name="dual_color_blend_by_location" value="true" />
 	</application>
 
         <application name="Unigine Heaven (64-bit)" executable="heaven_x64">
             <option name="allow_glsl_extension_directive_midshader" value="true" />
-            <!-- remove disable_blend_func_extended if 4.1 ever comes out -->
-            <option name="disable_blend_func_extended" value="true" />
+            <!-- remove dual_color_blend_by_location if 4.1 ever comes out -->
+            <option name="dual_color_blend_by_location" value="true" />
 	</application>
 
         <application name="Unigine Valley (32-bit)" executable="valley_x86">
             <option name="allow_glsl_extension_directive_midshader" value="true" />
-            <!-- remove disable_blend_func_extended if 1.1 ever comes out -->
-            <option name="disable_blend_func_extended" value="true" />
+            <!-- remove dual_color_blend_by_location if 1.1 ever comes out -->
+            <option name="dual_color_blend_by_location" value="true" />
 	</application>
 
         <application name="Unigine Valley (64-bit)" executable="valley_x64">
             <option name="allow_glsl_extension_directive_midshader" value="true" />
-            <!-- remove disable_blend_func_extended if 1.1 ever comes out -->
-            <option name="disable_blend_func_extended" value="true" />
+            <!-- remove dual_color_blend_by_location if 1.1 ever comes out -->
+            <option name="dual_color_blend_by_location" value="true" />
 	</application>
 
         <application name="Unigine OilRush (32-bit)" executable="OilRush_x86">
diff --git a/src/mesa/drivers/dri/common/xmlpool/t_options.h b/src/mesa/drivers/dri/common/xmlpool/t_options.h
index 4e5a7217ee2..55e926b239e 100644
--- a/src/mesa/drivers/dri/common/xmlpool/t_options.h
+++ b/src/mesa/drivers/dri/common/xmlpool/t_options.h
@@ -90,6 +90,11 @@ DRI_CONF_OPT_BEGIN_B(disable_blend_func_extended, def) \
         DRI_CONF_DESC(en,gettext("Disable dual source blending")) \
 DRI_CONF_OPT_END
 
+#define DRI_CONF_DUAL_COLOR_BLEND_BY_LOCATION(def) \
+DRI_CONF_OPT_BEGIN_B(dual_color_blend_by_location, def) \
+        DRI_CONF_DESC(en,gettext("Identify dual color blending sources by location rather than index")) \
+DRI_CONF_OPT_END
+
 #define DRI_CONF_DISABLE_GLSL_LINE_CONTINUATIONS(def) \
 DRI_CONF_OPT_BEGIN_B(disable_glsl_line_continuations, def) \
         DRI_CONF_DESC(en,gettext("Disable backslash-based line continuations in GLSL source")) \
diff --git a/src/mesa/drivers/dri/i965/brw_compiler.h b/src/mesa/drivers/dri/i965/brw_compiler.h
index 224ddb14ed1..748ffe58b0c 100644
--- a/src/mesa/drivers/dri/i965/brw_compiler.h
+++ b/src/mesa/drivers/dri/i965/brw_compiler.h
@@ -246,6 +246,7 @@ struct brw_wm_prog_key {
    bool compute_sample_id:1;
    unsigned line_aa:2;
    bool high_quality_derivatives:1;
+   bool force_dual_color_blend:1;
 
    uint16_t drawable_height;
    uint64_t input_slots_valid;
diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 9ba33396d36..1032e5a8175 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -750,6 +750,9 @@ brw_process_driconf_options(struct brw_context *brw)
 
    ctx->Const.AllowGLSLExtensionDirectiveMidShader =
       driQueryOptionb(options, "allow_glsl_extension_directive_midshader");
+
+   brw->dual_color_blend_by_location =
+      driQueryOptionb(options, "dual_color_blend_by_location");
 }
 
 GLboolean
diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
index 2a29dfe5eec..55d6723eab7 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -836,6 +836,7 @@ struct brw_context
    bool always_flush_cache;
    bool disable_throttling;
    bool precompile;
+   bool dual_color_blend_by_location;
 
    driOptionCache optionCache;
    /** @} */
diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index d7bcc1c5374..f9df2a4e3b6 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -130,7 +130,11 @@ fs_visitor::nir_setup_outputs()
          break;
       }
       case MESA_SHADER_FRAGMENT:
-         if (var->data.index > 0) {
+         if (key->force_dual_color_blend &&
+             var->data.location == FRAG_RESULT_DATA1) {
+            this->dual_src_output = reg;
+            this->do_dual_src = true;
+         } else if (var->data.index > 0) {
             assert(var->data.location == FRAG_RESULT_DATA0);
             assert(var->data.index == 1);
             this->dual_src_output = reg;
diff --git a/src/mesa/drivers/dri/i965/brw_wm.c b/src/mesa/drivers/dri/i965/brw_wm.c
index 39d644ea63a..78846dc3790 100644
--- a/src/mesa/drivers/dri/i965/brw_wm.c
+++ b/src/mesa/drivers/dri/i965/brw_wm.c
@@ -515,6 +515,10 @@ brw_wm_populate_key(struct brw_context *brw, struct brw_wm_prog_key *key)
    /* _NEW_BUFFERS */
    key->nr_color_regions = ctx->DrawBuffer->_NumColorDrawBuffers;
 
+   /* _NEW_COLOR */
+   key->force_dual_color_blend = brw->dual_color_blend_by_location &&
+      (ctx->Color.BlendEnabled & 1) && ctx->Color.Blend[0]._UsesDualSrc;
+
    /* _NEW_MULTISAMPLE, _NEW_COLOR, _NEW_BUFFERS */
    key->replicate_alpha = ctx->DrawBuffer->_NumColorDrawBuffers > 1 &&
       (ctx->Multisample.SampleAlphaToCoverage || ctx->Color.AlphaEnabled);
diff --git a/src/mesa/drivers/dri/i965/intel_screen.c b/src/mesa/drivers/dri/i965/intel_screen.c
index e1e1e62d26a..bca783aea86 100644
--- a/src/mesa/drivers/dri/i965/intel_screen.c
+++ b/src/mesa/drivers/dri/i965/intel_screen.c
@@ -79,6 +79,7 @@ DRI_CONF_BEGIN
       DRI_CONF_FORCE_GLSL_EXTENSIONS_WARN("false")
       DRI_CONF_DISABLE_GLSL_LINE_CONTINUATIONS("false")
       DRI_CONF_DISABLE_BLEND_FUNC_EXTENDED("false")
+      DRI_CONF_DUAL_COLOR_BLEND_BY_LOCATION("false")
       DRI_CONF_ALLOW_GLSL_EXTENSION_DIRECTIVE_MIDSHADER("false")
 
       DRI_CONF_OPT_BEGIN_B(shader_precompile, "true")