sna: Demote MOVE_READ if the GC operation covers the clip

If the write operation fills the entire clip, then we can demote and
possible avoid having to read back the clip from the GPU provided that
we do not need the destination data due to arithmetic operation or mask.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 50 insertions, 32 deletions

diff --git a/src/sna/sna_accel.c b/src/sna/sna_accel.c
index f8688c9e..0f21ffaa 100644
--- a/src/sna/sna_accel.c
+++ b/src/sna/sna_accel.c
@@ -796,7 +796,7 @@ _sna_pixmap_move_to_cpu(PixmapPtr pixmap, unsigned int flags)
 	     priv->gpu_damage));
 
 	if ((flags & MOVE_READ) == 0) {
-		assert(flags == MOVE_WRITE);
+		assert(flags & MOVE_WRITE);
 		sna_damage_destroy(&priv->gpu_damage);
 
 		if (priv->gpu && pixmap_inplace(sna, pixmap, priv)) {
@@ -1076,7 +1076,7 @@ sna_drawable_move_region_to_cpu(DrawablePtr drawable,
 	}
 
 	if ((flags & MOVE_READ) == 0) {
-		assert(flags == MOVE_WRITE);
+		assert(flags & MOVE_WRITE);
 
 		if (priv->stride && priv->gpu_bo &&
 		    region_inplace(sna, pixmap, region, priv)) {
@@ -1181,7 +1181,7 @@ sna_drawable_move_region_to_cpu(DrawablePtr drawable,
 		goto done;
 
 	if ((flags & MOVE_READ) == 0) {
-		assert(flags == MOVE_WRITE);
+		assert(flags & MOVE_WRITE);
 		sna_damage_subtract(&priv->gpu_damage, region);
 		goto done;
 	}
@@ -1380,32 +1380,38 @@ static bool alu_overwrites(uint8_t alu)
 	}
 }
 
-inline static unsigned drawable_gc_flags(DrawablePtr draw, GCPtr gc)
+inline static unsigned drawable_gc_flags(DrawablePtr draw,
+					 GCPtr gc,
+					 bool read)
 {
-	unsigned flags = MOVE_READ | MOVE_WRITE;
-
-	if (!USE_INPLACE)
-		return flags;
+	unsigned flags;
 
 	if (!alu_overwrites(gc->alu)) {
 		DBG(("%s: read due to alu %d\n", __FUNCTION__, gc->alu));
-		return flags;
+		return MOVE_READ | MOVE_WRITE;
 	}
 
 	if (!PM_IS_SOLID(draw, gc->planemask)) {
 		DBG(("%s: read due to planemask %lx\n",
 		     __FUNCTION__, gc->planemask));
-		return flags;
+		return MOVE_READ | MOVE_WRITE;
 	}
 
 	if (gc->fillStyle == FillStippled) {
 		DBG(("%s: read due to fill %d\n",
 		     __FUNCTION__, gc->fillStyle));
-		return flags;
+		return MOVE_READ | MOVE_WRITE;
 	}
 
 	DBG(("%s: try operating on drawable inplace\n", __FUNCTION__));
-	return flags | MOVE_INPLACE_HINT;
+	flags = MOVE_WRITE;
+	if (USE_INPLACE)
+		flags |= MOVE_INPLACE_HINT;
+	if (read) {
+		DBG(("%s: partial write\n", __FUNCTION__));
+		flags |= MOVE_READ;
+	}
+	return flags;
 }
 
 static bool
@@ -2806,7 +2812,8 @@ fallback:
 	if (!sna_gc_move_to_cpu(gc, drawable))
 		goto out;
 	if (!sna_drawable_move_region_to_cpu(drawable, &region,
-					     drawable_gc_flags(drawable, gc)))
+					     drawable_gc_flags(drawable, gc,
+							       true)))
 		goto out;
 
 	DBG(("%s: fbPutImage(%d, %d, %d, %d)\n",
@@ -3910,7 +3917,8 @@ fallback:
 	if (!sna_gc_move_to_cpu(gc, drawable))
 		goto out;
 	if (!sna_drawable_move_region_to_cpu(drawable, &region,
-					     drawable_gc_flags(drawable, gc)))
+					     drawable_gc_flags(drawable,
+							       gc, true)))
 		goto out;
 
 	fbFillSpans(drawable, gc, n, pt, width, sorted);
@@ -3946,7 +3954,8 @@ fallback:
 	if (!sna_gc_move_to_cpu(gc, drawable))
 		goto out;
 	if (!sna_drawable_move_region_to_cpu(drawable, &region,
-					     drawable_gc_flags(drawable, gc)))
+					     drawable_gc_flags(drawable,
+							       gc, true)))
 		goto out;
 
 	fbSetSpans(drawable, gc, src, pt, width, n, sorted);
@@ -4575,7 +4584,8 @@ fallback:
 	if (!sna_gc_move_to_cpu(gc, drawable))
 		goto out;
 	if (!sna_drawable_move_region_to_cpu(drawable, &region,
-					     drawable_gc_flags(drawable, gc)))
+					     drawable_gc_flags(drawable, gc,
+							       n > 1)))
 		goto out;
 
 	DBG(("%s: fbPolyPoint\n", __FUNCTION__));
@@ -5457,7 +5467,8 @@ fallback:
 	if (!sna_gc_move_to_cpu(gc, drawable))
 		goto out;
 	if (!sna_drawable_move_region_to_cpu(drawable, &region,
-					     drawable_gc_flags(drawable, gc)))
+					     drawable_gc_flags(drawable, gc,
+							       n > 2)))
 		goto out;
 
 	DBG(("%s: fbPolyLine\n", __FUNCTION__));
@@ -6313,7 +6324,8 @@ fallback:
 	if (!sna_gc_move_to_cpu(gc, drawable))
 		goto out;
 	if (!sna_drawable_move_region_to_cpu(drawable, &region,
-					     drawable_gc_flags(drawable, gc)))
+					     drawable_gc_flags(drawable, gc,
+							       n > 1)))
 		goto out;
 
 	DBG(("%s: fbPolySegment\n", __FUNCTION__));
@@ -6866,7 +6878,8 @@ fallback:
 	if (!sna_gc_move_to_cpu(gc, drawable))
 		goto out;
 	if (!sna_drawable_move_region_to_cpu(drawable, &region,
-					     drawable_gc_flags(drawable, gc)))
+					     drawable_gc_flags(drawable,
+							       gc, true)))
 		goto out;
 
 	DBG(("%s: fbPolyRectangle\n", __FUNCTION__));
@@ -6995,7 +7008,8 @@ fallback:
 	if (!sna_gc_move_to_cpu(gc, drawable))
 		goto out;
 	if (!sna_drawable_move_region_to_cpu(drawable, &region,
-					     drawable_gc_flags(drawable, gc)))
+					     drawable_gc_flags(drawable,
+							       gc, true)))
 		goto out;
 
 	/* XXX may still fallthrough to miZeroPolyArc */
@@ -8515,11 +8529,9 @@ fallback:
 	if (!sna_gc_move_to_cpu(gc, draw))
 		goto out;
 
-	flags = MOVE_WRITE;
-	if (gc->fillStyle == FillStippled  ||
-	    !(gc->alu == GXcopy || gc->alu == GXclear || gc->alu == GXset))
-		flags |= MOVE_READ;
-	if (!sna_drawable_move_region_to_cpu(draw, &region, flags))
+	if (!sna_drawable_move_region_to_cpu(draw, &region,
+					     drawable_gc_flags(draw, gc,
+							       n > 1)))
 		goto out;
 
 	DBG(("%s: fallback - fbPolyFillRect\n", __FUNCTION__));
@@ -8971,7 +8983,8 @@ force_fallback:
 			goto out;
 
 		if (!sna_drawable_move_region_to_cpu(drawable, &region,
-						     MOVE_READ | MOVE_WRITE))
+						     drawable_gc_flags(drawable,
+								       gc, true)))
 			goto out;
 
 		DBG(("%s: fallback -- fbPolyGlyphBlt\n", __FUNCTION__));
@@ -9052,7 +9065,7 @@ force_fallback:
 		if (!sna_gc_move_to_cpu(gc, drawable))
 			goto out;
 		if (!sna_drawable_move_region_to_cpu(drawable, &region,
-						     MOVE_READ | MOVE_WRITE))
+						     drawable_gc_flags(drawable, gc, true)))
 			goto out;
 
 		DBG(("%s: fallback -- fbPolyGlyphBlt\n", __FUNCTION__));
@@ -9133,7 +9146,8 @@ force_fallback:
 		if (!sna_gc_move_to_cpu(gc, drawable))
 			goto out;
 		if (!sna_drawable_move_region_to_cpu(drawable, &region,
-						     drawable_gc_flags(drawable, gc)))
+						     drawable_gc_flags(drawable,
+								       gc, n > 1)))
 			goto out;
 
 		DBG(("%s: fallback -- fbImageGlyphBlt\n", __FUNCTION__));
@@ -9207,7 +9221,8 @@ force_fallback:
 		if (!sna_gc_move_to_cpu(gc, drawable))
 			goto out;
 		if(!sna_drawable_move_region_to_cpu(drawable, &region,
-						    drawable_gc_flags(drawable, gc)))
+						    drawable_gc_flags(drawable,
+								      gc, n > 1)))
 			goto out;
 
 		DBG(("%s: fallback -- fbImageGlyphBlt\n", __FUNCTION__));
@@ -9457,7 +9472,8 @@ fallback:
 	if (!sna_gc_move_to_cpu(gc, drawable))
 		goto out;
 	if (!sna_drawable_move_region_to_cpu(drawable, &region,
-					     drawable_gc_flags(drawable, gc)))
+					     drawable_gc_flags(drawable,
+							       gc, n > 1)))
 		goto out;
 
 	DBG(("%s: fallback -- fbImageGlyphBlt\n", __FUNCTION__));
@@ -9524,7 +9540,8 @@ fallback:
 	if (!sna_gc_move_to_cpu(gc, drawable))
 		goto out;
 	if (!sna_drawable_move_region_to_cpu(drawable, &region,
-					     MOVE_READ | MOVE_WRITE))
+					     drawable_gc_flags(drawable,
+							       gc, true)))
 		goto out;
 	DBG(("%s: fallback -- fbPolyGlyphBlt\n", __FUNCTION__));
 	fbPolyGlyphBlt(drawable, gc, x, y, n, info, base);
@@ -9700,7 +9717,8 @@ sna_push_pixels(GCPtr gc, PixmapPtr bitmap, DrawablePtr drawable,
 	if (!sna_pixmap_move_to_cpu(bitmap, MOVE_READ))
 		goto out;
 	if (!sna_drawable_move_region_to_cpu(drawable, &region,
-					     drawable_gc_flags(drawable, gc)))
+					     drawable_gc_flags(drawable,
+							       gc, false)))
 		goto out;
 
 	DBG(("%s: fallback, fbPushPixels(%d, %d, %d %d)\n",