i965/vs: Take attributes into account when deciding urb_entry_size.

Both the VF and VS share space in the URB.  First, the VF stores
attributes (shader inputs) there.  The VS then reads the attributes,
executes, and reuses the space to store varyings (shader outputs).

Thus, we need to calculate the amount of URB space necessary for inputs,
outputs, and pick whichever is greater.

The old VS backend correctly did this (brw_vs_emit.c:408), but the new
VS backend only considered outputs.

Fixes vertex scrambling in GLBenchmark PRO on Ivybridge.

NOTE: This is a candidate for the 8.0 branch.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41318
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_emit.cpp b/src/mesa/drivers/dri/i965/brw_vec4_emit.cpp
index a618614c73c444b3dcf9815764e45bde074153a1..dbe4dd093dd29deeb5155a3334807f063c103e42 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4_emit.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_emit.cpp
@@ -25,6 +25,7 @@
 
 extern "C" {
 #include "brw_eu.h"
+#include "main/macros.h"
 };
 
 using namespace brw;
@@ -95,6 +96,13 @@ vec4_visitor::setup_attributes(int payload_reg)
 
    prog_data->urb_read_length = (nr_attributes + 1) / 2;
 
+   unsigned vue_entries = MAX2(nr_attributes, c->vue_map.num_slots);
+
+   if (intel->gen == 6)
+      c->prog_data.urb_entry_size = ALIGN(vue_entries, 8) / 8;
+   else
+      c->prog_data.urb_entry_size = ALIGN(vue_entries, 4) / 4;
+
    return payload_reg + nr_attributes;
 }
 

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index ecabcc81e9e5125d36224150505ccbe2bd5dcc10..06bde92c8d8e7452ecb1f981e3ebca1d4fb54e71 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -2286,11 +2286,6 @@ vec4_visitor::emit_urb_writes()
        */
       inst->offset = (max_usable_mrf - base_mrf) / 2;
    }
-
-   if (intel->gen == 6)
-      c->prog_data.urb_entry_size = ALIGN(c->vue_map.num_slots, 8) / 8;
-   else
-      c->prog_data.urb_entry_size = ALIGN(c->vue_map.num_slots, 4) / 4;
 }
 
 src_reg