[Mesa-dev] [PATCH] i965: Add driconf option clamp_max_samples

[Chad Versace]

This clamps GL_MAX_SAMPLES to the given value. If negative, then no
clamping occurs.

CC: Paul Berry <stereotype441 at gmail.com>
CC: Eric Anholt <eric at anholt.net>
Signed-off-by: Chad Versace <chad.versace at linux.intel.com>
---


This patch lives on my branch driconf-clamp-max_samples.


 src/mesa/drivers/dri/i965/brw_context.c  | 41 ++++++++++++++++++++++++--------
 src/mesa/drivers/dri/i965/intel_screen.c |  8 ++++++-
 2 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 38147e9..32faf72 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -273,6 +273,10 @@ brw_initialize_context_constants(struct brw_context *brw)
 {
    struct gl_context *ctx = &brw->ctx;
 
+   int max_samples;
+   const int *legal_max_samples;
+   int clamp_max_samples;
+
    ctx->Const.QueryCounterBits.Timestamp = 36;
 
    ctx->Const.StripTextureBorder = true;
@@ -333,19 +337,36 @@ brw_initialize_context_constants(struct brw_context *brw)
 
    ctx->Const.AlwaysUseGetTransformFeedbackVertexCount = true;
 
-   if (brw->gen == 6) {
-      ctx->Const.MaxSamples = 4;
-      ctx->Const.MaxColorTextureSamples = 4;
-      ctx->Const.MaxDepthTextureSamples = 4;
-      ctx->Const.MaxIntegerSamples = 4;
-   } else if (brw->gen >= 7) {
-      ctx->Const.MaxSamples = 8;
-      ctx->Const.MaxColorTextureSamples = 8;
-      ctx->Const.MaxDepthTextureSamples = 8;
-      ctx->Const.MaxIntegerSamples = 8;
+   if (brw->gen >= 7)
       ctx->Const.MaxProgramTextureGatherComponents = 4;
+
+   if (brw->gen >= 7) {
+      legal_max_samples = (int[]){8, 4, 0};
+   } else if (brw->gen == 6) {
+      legal_max_samples = (int[]){4, 0};
+   } else {
+      legal_max_samples = (int[]){0};
+   }
+
+   clamp_max_samples = driQueryOptioni(&brw->optionCache, "clamp_max_samples");
+   if (clamp_max_samples < 0) {
+      clamp_max_samples = INT_MAX;
+   }
+
+   /* Set max_samples = min(max(legal_max_samples), clamp_max_samples). */
+   max_samples = 0;
+   for (int i = 0; legal_max_samples[i] != 0; ++i) {
+      if (legal_max_samples[i] <= clamp_max_samples) {
+         max_samples = legal_max_samples[i];
+         break;
+      }
    }
 
+   ctx->Const.MaxSamples = max_samples;
+   ctx->Const.MaxColorTextureSamples = max_samples;
+   ctx->Const.MaxDepthTextureSamples = max_samples;
+   ctx->Const.MaxIntegerSamples = max_samples;
+
    ctx->Const.MinLineWidth = 1.0;
    ctx->Const.MinLineWidthAA = 1.0;
    ctx->Const.MaxLineWidth = 5.0;
diff --git a/src/mesa/drivers/dri/i965/intel_screen.c b/src/mesa/drivers/dri/i965/intel_screen.c
index eafafa2..ce8124b 100644
--- a/src/mesa/drivers/dri/i965/intel_screen.c
+++ b/src/mesa/drivers/dri/i965/intel_screen.c
@@ -63,11 +63,17 @@ DRI_CONF_BEGIN
       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
       DRI_CONF_FORCE_S3TC_ENABLE("false")
+
+      DRI_CONF_OPT_BEGIN(clamp_max_samples, int, -1)
+              DRI_CONF_DESC(en, "Clamp the value of GL_MAX_SAMPLES to the "
+                            "given integer. If negative, then do not clamp.")
+      DRI_CONF_OPT_END
    DRI_CONF_SECTION_END
+
    DRI_CONF_SECTION_DEBUG
       DRI_CONF_NO_RAST("false")
       DRI_CONF_ALWAYS_FLUSH_BATCH("false")
-- 
1.8.3.1