[Mesa-dev] [PATCH] r300/compiler: Prevent the fragmentation of TEX blocks in the pair scheduler.

[tstellar at gmail.com]

From: Tom Stellard <tstellar at gmail.com>

This fixes bug:

https://bugs.freedesktop.org/show_bug.cgi?id=25109
---
 .../dri/r300/compiler/radeon_pair_schedule.c       |   39 +++++++++++++-------
 1 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/src/mesa/drivers/dri/r300/compiler/radeon_pair_schedule.c b/src/mesa/drivers/dri/r300/compiler/radeon_pair_schedule.c
index a279549..0641be5 100644
--- a/src/mesa/drivers/dri/r300/compiler/radeon_pair_schedule.c
+++ b/src/mesa/drivers/dri/r300/compiler/radeon_pair_schedule.c
@@ -208,21 +208,32 @@ static void emit_all_tex(struct schedule_state * s, struct rc_instruction * befo
 
 	assert(s->ReadyTEX);
 
-	/* Don't let the ready list change under us! */
-	readytex = s->ReadyTEX;
-	s->ReadyTEX = 0;
-
-	/* Node marker for R300 */
-	struct rc_instruction * inst_begin = rc_insert_new_instruction(s->C, before->Prev);
-	inst_begin->U.I.Opcode = RC_OPCODE_BEGIN_TEX;
-
-	/* Link texture instructions back in */
-	while(readytex) {
-		struct schedule_instruction * tex = readytex;
-		readytex = readytex->NextReady;
+	if(s->ReadyTEX){
+		/* Node marker for R300 */
+		struct rc_instruction * inst_begin =
+				rc_insert_new_instruction(s->C, before->Prev);
+		inst_begin->U.I.Opcode = RC_OPCODE_BEGIN_TEX;
+	}
 
-		rc_insert_instruction(before->Prev, tex->Instruction);
-		commit_instruction(s, tex);
+	/* The purpose of this outer loop is to emit TEX instruction that
+	 * have become ready as a result of the inner loop.  This prevents
+	 * the fragmentation of TEX blocks, which for some shaders (in Civ4
+	 * for example) was creating too many texture indirections on r300
+	 * cards.
+	 */
+	while(s->ReadyTEX){
+		/* Don't let the ready list change under us! */
+		readytex = s->ReadyTEX;
+		s->ReadyTEX = 0;
+
+		/* Link texture instructions back in */
+		while(readytex) {
+			struct schedule_instruction * tex = readytex;
+			readytex = readytex->NextReady;
+
+			rc_insert_instruction(before->Prev, tex->Instruction);
+			commit_instruction(s, tex);
+		}
 	}
 }
 
-- 
1.6.4.4