Here's my patch below. Sorry for late response. I wonder what pixmap_is_scanout does. It always returns FALSE. Patch for intel driver 2.14.0 (the one in Ubuntu distro).

    Gen6 wait for scanline event support

-------------------------------- src/i830_reg.h --------------------------------
index 93d03cf..0a5946c 100644
@@ -65,6 +65,19 @@
 #define MI_LOAD_SCAN_LINES_DISPLAY_PIPEA	(0)
 #define MI_LOAD_SCAN_LINES_DISPLAY_PIPEB	(0x1<<20)
 
+/* Gen6 wait for scan line support */
+#define MI_LOAD_REGISTER_IMM				(0x22<<23)
+#define MI_DISPLAY_PIPEA_SCAN_LINE_WAIT		(1)
+#define MI_DISPLAY_PIPEB_SCAN_LINE_WAIT		(1<<8)
+#define MI_DISPLAY_PIPEA_VBLANK_WAIT		(1<<3)
+#define MI_DISPLAY_PIPEB_VBLANK_WAIT		(1<<11)
+
+/* Scan lines register */
+#define DE_LOAD_SL_ADDR		(0x4f100)
+#define DE_LOAD_SL_PIPEA		(0x110<<29)
+#define DE_LOAD_SL_PIPEB		(0x111<<29)
+#define DERRMR_ADDR	(0x44050)
+
 /* BLT commands */
 #define COLOR_BLT_CMD		((2<<29)|(0x40<<22)|(0x3))
 #define COLOR_BLT_WRITE_ALPHA	(1<<21)

------------------------------ src/intel_video.c ------------------------------
index 5294f73..506178f 100644
@@ -1365,6 +1365,83 @@ intel_wait_for_scanline(ScrnInfoPtr scrn, PixmapPtr pixmap,
 	ADVANCE_BATCH();
 }
 
+static void
+intel_wait_for_scanline_gen6(ScrnInfoPtr scrn, PixmapPtr pixmap,
+			xf86CrtcPtr crtc, RegionPtr clipBoxes)
+{
+	intel_screen_private *intel = intel_get_screen_private(scrn);
+	pixman_box16_t box, crtc_box;
+	int pipe, event;
+	Bool full_height;
+	int y1, y2;
+
+	pipe = -1;
+	if (pixmap_is_scanout(pixmap))
+	{
+		pipe = intel_crtc_to_pipe(crtc);
+	}
+	if (pipe < 0)
+		return;
+
+	box = *REGION_EXTENTS(unused, clipBoxes);
+
+	if (crtc->transform_in_use)
+		pixman_f_transform_bounds(&crtc->f_framebuffer_to_crtc, &box);
+
+	/* We could presume the clip was correctly computed... */
+	intel_crtc_box(crtc, &crtc_box);
+	intel_box_intersect(&box, &crtc_box, &box);
+
+	/*
+	 * Make sure we don't wait for a scanline that will
+	 * never occur
+	 */
+	y1 = (crtc_box.y1 <= box.y1) ? box.y1 - crtc_box.y1 : 0;
+	y2 = (box.y2 <= crtc_box.y2) ?
+		box.y2 - crtc_box.y1 : crtc_box.y2 - crtc_box.y1;
+
+	if (y2 <= y1)
+		return;
+
+	full_height = FALSE;
+	if (y1 == 0 && y2 == (crtc_box.y2 - crtc_box.y1))
+		full_height = TRUE;
+
+	if (pipe == 0) {
+		pipe = DE_LOAD_SL_PIPEA;
+		event = MI_DISPLAY_PIPEA_SCAN_LINE_WAIT;
+		if (full_height)
+			event = MI_DISPLAY_PIPEA_VBLANK_WAIT;
+	} else {
+		pipe = DE_LOAD_SL_PIPEB;
+		event = MI_DISPLAY_PIPEB_SCAN_LINE_WAIT;
+		if (full_height)
+			event = MI_DISPLAY_PIPEB_VBLANK_WAIT;
+	}
+
+	/* According to docs only upper 10 bits are significant */
+	if(!(y2 & 0x3))
+		y2 += 8;
+
+
+	y1 &= 0x1ff8;
+	y2 &= 0x1ff8;
+
+	if (crtc->mode.Flags & V_INTERLACE) {
+		/* DSL count field lines */
+		y1 /= 2;
+		y2 /= 2;
+	}
+
+	BEGIN_BATCH(4);
+	OUT_BATCH(MI_LOAD_REGISTER_IMM | 1);
+	OUT_BATCH(DE_LOAD_SL_ADDR);
+	OUT_BATCH(pipe | (y1 << 16) | y2);
+	OUT_BATCH(MI_WAIT_FOR_EVENT | event);
+	ADVANCE_BATCH();
+}
+
+
 static Bool
 intel_setup_video_buffer(ScrnInfoPtr scrn, intel_adaptor_private *adaptor_priv,
 			 int alloc_size, int id, unsigned char *buf)
@@ -1578,8 +1655,11 @@ I830PutImageTextured(ScrnInfoPtr scrn,
 			return BadAlloc;
 	}
 
-	if (crtc && adaptor_priv->SyncToVblank != 0 && INTEL_INFO(intel)->gen < 60) {
-		intel_wait_for_scanline(scrn, pixmap, crtc, clipBoxes);
+	if (crtc && adaptor_priv->SyncToVblank != 0) {
+		if(INTEL_INFO(intel)->gen < 60)
+			intel_wait_for_scanline(scrn, pixmap, crtc, clipBoxes);
+		else
+			intel_wait_for_scanline_gen6(scrn, pixmap, crtc, clipBoxes);
 	}
 
 	if (INTEL_INFO(intel)->gen >= 60) {