shadow: Use a cacheable shadow for all generations

Always avoid direct rendering to the uncached scanout buffer,
redirecting all 2D access to the shadow instead. Then for the couple of
platforms where either the BLT is not ready or cannot be trusted (i8xx)
perform the front buffer fixup using the uncached writes from the CPU.

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

1 files changed, 41 insertions, 19 deletions

diff --git a/src/intel_shadow.c b/src/intel_shadow.c
index eb5f1add..37e4cd2d 100644
--- a/src/intel_shadow.c
+++ b/src/intel_shadow.c
@@ -64,6 +64,40 @@ intel_shadow_create_bo(intel_screen_private *intel,
 	return bo;
 }
 
+static void intel_shadow_memcpy(intel_screen_private *intel)
+{
+	char *src_data, *dst_data;
+	unsigned int src_pitch, dst_pitch;
+	RegionPtr region;
+	BoxPtr box;
+	int n;
+
+	if (drm_intel_gem_bo_map_gtt(intel->front_buffer))
+		return;
+
+	src_data = intel->shadow_buffer;
+	dst_data = intel->front_buffer->virtual;
+
+	src_pitch = intel->shadow_stride;
+	dst_pitch = intel->front_pitch;
+
+	region = DamageRegion(intel->shadow_damage);
+	box = REGION_RECTS(region);
+	n = REGION_NUM_RECTS(region);
+	while (n--) {
+		char *src = src_data + box->y1*src_pitch + box->x1*intel->cpp;
+		char *dst = dst_data + box->y1*dst_pitch + box->x1*intel->cpp;
+		int len = (box->x2 - box->x1)*intel->cpp;
+		int row = box->y2 - box->y1;
+		while (row--) {
+			memcpy(dst, src, len);
+			src += src_pitch;
+			dst += dst_pitch;
+		}
+		box++;
+	}
+}
+
 void intel_shadow_blt(intel_screen_private *intel)
 {
 	ScrnInfoPtr scrn = intel->scrn;
@@ -73,6 +107,12 @@ void intel_shadow_blt(intel_screen_private *intel)
 	BoxPtr box;
 	int n;
 
+	/* Can we trust the BLT? Otherwise do an uncached mmecy. */
+	if (IS_I8XX(intel) || IS_GEN6(intel)) {
+		intel_shadow_memcpy(intel);
+		return;
+	}
+
 	dst_pitch = intel->front_pitch;
 
 	blt = XY_SRC_COPY_BLT_CMD;
@@ -124,8 +164,7 @@ void intel_shadow_blt(intel_screen_private *intel)
 
 		ADVANCE_BATCH();
 
-		if (bo != intel->shadow_buffer)
-			drm_intel_bo_unreference(bo);
+		drm_intel_bo_unreference(bo);
 		box++;
 	}
 }
@@ -139,23 +178,6 @@ void intel_shadow_create(struct intel_screen_private *intel)
 	void *buffer;
 
 	pixmap = screen->GetScreenPixmap(screen);
-	if (IS_I8XX(intel) || IS_GEN6(intel)) {
-		/* Okay, this is a lie. We just use the scanout directly
-		 * via a GTT (uncached) mapping and never attempt anything
-		 * more dangerous...
-		 */
-		if (intel->front_buffer &&
-		    drm_intel_gem_bo_map_gtt(intel->front_buffer) == 0) {
-			screen->ModifyPixmapHeader(pixmap,
-						   scrn->virtualX,
-						   scrn->virtualY,
-						   -1, -1,
-						   intel->front_pitch,
-						   intel->front_buffer->virtual);
-		}
-		return;
-	}
-
 	stride = intel->cpp*scrn->virtualX;
 	buffer = malloc(stride * scrn->virtualY);
 	if (buffer &&