From 64e45993cf9d13b5900dc6b8afacffdfea14fa7f Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 22 Apr 2015 20:15:38 +0100
Subject: [PATCH] sna: Fix interpretation of SWCTRL

Bspec says it is an override for the source format, irrespective of
the tiling bit supplied in the command packet. So we need to apply the
FLUSH+LRI more often.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 src/sna/kgem.c | 44 +++++++++++++++++---------------------------
 1 file changed, 17 insertions(+), 27 deletions(-)

diff --git a/src/sna/kgem.c b/src/sna/kgem.c
index 76e69135..d1902552 100644
--- a/src/sna/kgem.c
+++ b/src/sna/kgem.c
@@ -2209,7 +2209,9 @@ static void kgem_clear_swctrl(struct kgem *kgem)
 
 	*b++ = MI_LOAD_REGISTER_IMM;
 	*b++ = BCS_SWCTRL;
-	*b++ = kgem->bcs_state << 16;
+	*b++ = (BCS_SRC_Y | BCS_DST_Y) << 16;
+
+	kgem->bcs_state = 0;
 }
 
 static uint32_t kgem_end_batch(struct kgem *kgem)
@@ -3557,7 +3559,6 @@ void kgem_reset(struct kgem *kgem)
 	kgem->needs_reservation = false;
 	kgem->flush = 0;
 	kgem->batch_flags = kgem->batch_flags_base;
-	kgem->bcs_state = 0;
 	assert(kgem->batch);
 
 	kgem->next_request = __kgem_request_alloc(kgem);
@@ -6196,60 +6197,49 @@ void __kgem_bcs_set_tiling(struct kgem *kgem,
 			   struct kgem_bo *src,
 			   struct kgem_bo *dst)
 {
-	uint32_t state, mask, *b;
+	uint32_t state, *b;
 
 	DBG(("%s: src handle=%d:tiling=%d, dst handle=%d:tiling=%d\n",
 	     __FUNCTION__,
 	     src ? src->handle : 0, src ? src->tiling : 0,
 	     dst ? dst->handle : 0, dst ? dst->tiling : 0));
 	assert(kgem->mode == KGEM_BLT);
+	assert(dst == NULL || kgem_bo_can_blt(kgem, dst));
+	assert(src == NULL || kgem_bo_can_blt(kgem, src));
 
-	mask = state = 0;
-	if (dst && dst->tiling) {
-		assert(kgem_bo_can_blt(kgem, dst));
-		mask |= BCS_DST_Y;
-		if (dst->tiling == I915_TILING_Y)
-			state |= BCS_DST_Y;
-	}
+	state = 0;
+	if (dst && dst->tiling == I915_TILING_Y)
+		state |= BCS_DST_Y;
+	if (src && src->tiling == I915_TILING_Y)
+		state |= BCS_SRC_Y;
 
-	if (src && src->tiling) {
-		assert(kgem_bo_can_blt(kgem, src));
-		mask |= BCS_SRC_Y;
-		if (src->tiling == I915_TILING_Y)
-			state |= BCS_SRC_Y;
-	}
-
-	if ((kgem->bcs_state & mask) == state)
+	if (kgem->bcs_state == state)
 		return;
 
 	DBG(("%s: updating SWCTRL %x -> %x\n", __FUNCTION__,
-	     kgem->bcs_state, (kgem->bcs_state & ~mask) | state));
+	     kgem->bcs_state, state));
 
 	/* Over-estimate space in case we need to re-emit the cmd packet */
 	if (!kgem_check_batch(kgem, 24)) {
 		_kgem_submit(kgem);
 		_kgem_set_mode(kgem, KGEM_BLT);
+		if (state == 0)
+			return;
 	}
 
 	b = kgem->batch + kgem->nbatch;
 	if (kgem->nbatch) {
-		DBG(("%s: emitting flush before SWCTRL LRI\n",
-		     __FUNCTION__));
 		*b++ = MI_FLUSH_DW;
 		*b++ = 0;
 		*b++ = 0;
 		*b++ = 0;
 	}
-
-	DBG(("%s: emitting SWCTRL LRI to %x\n",
-	     __FUNCTION__, mask << 16 | state));
 	*b++ = MI_LOAD_REGISTER_IMM;
 	*b++ = BCS_SWCTRL;
-	*b++ = mask << 16 | state;
+	*b++ = (BCS_SRC_Y | BCS_DST_Y) << 16 | state;
 	kgem->nbatch = b - kgem->batch;
 
-	kgem->bcs_state &= ~mask;
-	kgem->bcs_state |= state;
+	kgem->bcs_state = state;
 }
 
 uint32_t kgem_add_reloc(struct kgem *kgem,