src/sna/kgem.c

@@ -1944,6 +1944,19 @@ static uint64_t get_gtt_size(int fd)
 	return aperture.aper_size;
 }
 
+static int get_gtt_type(int fd)
+{
+        struct drm_i915_getparam p;
+        int val = 0;
+
+        memset(&p, 0, sizeof(p));
+        p.param = I915_PARAM_HAS_ALIASING_PPGTT;
+        p.value = &val;
+
+	drmIoctl(fd, DRM_IOCTL_I915_GETPARAM, &p);
+	return val;
+}
+
 void kgem_init(struct kgem *kgem, int fd, struct pci_device *dev, unsigned gen)
 {
 	size_t totalram;
@@ -2108,6 +2121,8 @@ void kgem_init(struct kgem *kgem, int fd, struct pci_device *dev, unsigned gen)
 	     !DBG_NO_CPU && (kgem->has_llc | kgem->has_userptr | kgem->has_caching),
 	     kgem->has_llc, kgem->has_caching, kgem->has_userptr));
 
+	kgem->has_full_ppgtt = get_gtt_type(fd) > 1;
+
 	gtt_size = get_gtt_size(fd);
 	kgem->aperture_total = gtt_size;
 	kgem->aperture_high = gtt_size * 3/4;

src/sna/kgem.h

@@ -191,6 +191,7 @@ struct kgem {
 	uint32_t has_pinned_batches :1;
 	uint32_t has_caching :1;
 	uint32_t has_coherent_mmap_gtt :1;
+	uint32_t has_full_ppgtt :1;
 	uint32_t has_llc :1;
 	uint32_t has_wt :1;
 	uint32_t has_no_reloc :1;

src/sna/sna_composite.c

@@ -649,15 +649,15 @@ sna_composite(CARD8 op,
 	      CARD16 width, CARD16 height)
 {
 	PixmapPtr pixmap = get_drawable_pixmap(dst->pDrawable);
-	struct sna *sna = to_sna_from_pixmap(pixmap);
 	struct sna_pixmap *priv;
 	struct sna_composite_op tmp;
 	RegionRec region;
+	struct sna *sna;
 	int dx, dy;
 
 	DBG(("%s(pixmap=%ld, op=%d, src=%ld+(%d, %d), mask=%ld+(%d, %d), dst=%ld+(%d, %d)+(%d, %d), size=(%d, %d)\n",
 	     __FUNCTION__,
-	     pixmap->drawable.serialNumber, op,
+	     pixmap ? pixmap->drawable.serialNumber : 0, op,
 	     get_picture_id(src), src_x, src_y,
 	     get_picture_id(mask), mask_x, mask_y,
 	     get_picture_id(dst), dst_x, dst_y,
@@ -672,8 +672,7 @@ sna_composite(CARD8 op,
 	if (op == PictOpClear) {
 		DBG(("%s: discarding source and mask for clear\n", __FUNCTION__));
 		mask = NULL;
-		if (sna->clear)
-			src = sna->clear;
+		src = NULL;
 	}
 
 	if (!sna_compute_composite_region(&region,
@@ -694,11 +693,6 @@ sna_composite(CARD8 op,
 	if (NO_COMPOSITE)
 		goto fallback;
 
-	if (wedged(sna)) {
-		DBG(("%s: fallback -- wedged\n", __FUNCTION__));
-		goto fallback;
-	}
-
 	if (!can_render_to_picture(dst)) {
 		DBG(("%s: fallback due to unhandled picture\n", __FUNCTION__));
 		goto fallback;
@@ -711,6 +705,15 @@ sna_composite(CARD8 op,
 		goto fallback;
 	}
 
+	sna = to_sna_from_pixmap(pixmap);
+	if (wedged(sna)) {
+		DBG(("%s: fallback -- wedged\n", __FUNCTION__));
+		goto fallback;
+	}
+
+	if (op == PictOpClear)
+		src = sna->clear;
+
 	if (use_cpu(pixmap, priv, op, width, height) &&
 	    !picture_is_gpu(sna, src, PREFER_GPU_RENDER) &&
 	    !picture_is_gpu(sna, mask, PREFER_GPU_RENDER)) {

src/sna/sna_driver.c

@@ -459,7 +459,18 @@ static bool enable_tear_free(struct sna *sna)
 	if (sna->flags & SNA_LINEAR_FB)
 		return false;
 
-	/* Under certain conditions, we should enable TearFree by default,
+	/*
+	 * On recent HW, where the display surfaces are in a seperate GTT
+	 * to userspace, there is much less contention on global resources
+	 * and also we can assume there is much more memory bandwidth
+	 * available (i.e. gen8+). This HW should rarely be under such
+	 * constaints as to need to disable TearFree, so enable by default.
+	 */
+	if (sna->kgem.has_full_ppgtt)
+		return true;
+
+	/*
+	 * Under certain conditions, we should enable TearFree by default,
 	 * for example when the hardware requires pageflipping to run within
 	 * its power/performance budget.
 	 */