i965: Remove "disable_derivative_optimization" driconf option.

This was added in September 2013 when we first implemented the fast
(but lower quality) derivatives.  A quick Google search didn't turn
up anyone using or recommending the option, so I suspect no one does.

Applications that want to control the quality of their derivatives can
use the new GL_ARB_derivative_control extension, or use the glHint
mechanism.  The driconf option seems superfluous.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>

5 files changed, 2 insertions, 21 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 8b0f391..5830b6e 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -630,9 +630,6 @@ brw_process_driconf_options(struct brw_context *brw)
       brw->disable_throttling = true;
    }
 
-   brw->disable_derivative_optimization =
-      driQueryOptionb(&brw->optionCache, "disable_derivative_optimization");
-
    brw->precompile = driQueryOptionb(&brw->optionCache, "shader_precompile");
 
    ctx->Const.ForceGLSLExtensionsWarn =
diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
index c4e96de..b0f699f 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -1019,7 +1019,6 @@ struct brw_context
    bool always_flush_cache;
    bool disable_throttling;
    bool precompile;
-   bool disable_derivative_optimization;
 
    driOptionCache optionCache;
    /** @} */
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 5ed4233..c6cd73b 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3793,12 +3793,6 @@ brw_fs_precompile(struct gl_context *ctx,
                           key.nr_color_regions > 1;
    }
 
-   /* GL_FRAGMENT_SHADER_DERIVATIVE_HINT is almost always GL_DONT_CARE.  The
-    * quality of the derivatives is likely to be determined by the driconf
-    * option.
-    */
-   key.high_quality_derivatives = brw->disable_derivative_optimization;
-
    key.program_string_id = bfp->id;
 
    uint32_t old_prog_offset = brw->wm.base.prog_offset;
diff --git a/src/mesa/drivers/dri/i965/brw_wm.c b/src/mesa/drivers/dri/i965/brw_wm.c
index 0183852..fe36dd4 100644
--- a/src/mesa/drivers/dri/i965/brw_wm.c
+++ b/src/mesa/drivers/dri/i965/brw_wm.c
@@ -468,13 +468,8 @@ static void brw_wm_populate_key( struct brw_context *brw,
    key->line_aa = line_aa;
 
    /* _NEW_HINT */
-   if (brw->disable_derivative_optimization) {
-      key->high_quality_derivatives =
-         ctx->Hint.FragmentShaderDerivative != GL_FASTEST;
-   } else {
-      key->high_quality_derivatives =
-         ctx->Hint.FragmentShaderDerivative == GL_NICEST;
-   }
+   key->high_quality_derivatives =
+      ctx->Hint.FragmentShaderDerivative == GL_NICEST;
 
    if (brw->gen < 6)
       key->stats_wm = brw->stats_wm;
diff --git a/src/mesa/drivers/dri/i965/intel_screen.c b/src/mesa/drivers/dri/i965/intel_screen.c
index 6618c1a..cea7ddf 100644
--- a/src/mesa/drivers/dri/i965/intel_screen.c
+++ b/src/mesa/drivers/dri/i965/intel_screen.c
@@ -61,10 +61,6 @@ DRI_CONF_BEGIN
       DRI_CONF_OPT_BEGIN_B(hiz, "true")
 	 DRI_CONF_DESC(en, "Enable Hierarchical Z on gen6+")
       DRI_CONF_OPT_END
-
-      DRI_CONF_OPT_BEGIN_B(disable_derivative_optimization, "false")
-	 DRI_CONF_DESC(en, "Derivatives with finer granularity by default")
-      DRI_CONF_OPT_END
    DRI_CONF_SECTION_END
 
    DRI_CONF_SECTION_QUALITY