r600: cubemap levels seem to be aligned to 8 images

src/mesa/drivers/dri/radeon/radeon_mipmap_tree.c

@@ -177,6 +177,12 @@ static void calculate_miptree_layout_r300(radeonContextPtr rmesa, radeon_mipmap_
 
 		for(face = 0; face < mt->faces; face++)
 			compute_tex_image_offset(rmesa, mt, face, level, &curOffset);
+		/* r600 cube levels seems to be aligned to 8 faces but
+		 * we have separate register for 1'st level offset so add
+		 * 2 image alignment after 1'st mip level */
+		if(rmesa->radeonScreen->chip_family >= CHIP_FAMILY_R600 &&
+		   level >= 1)
+			curOffset += 2 * mt->levels[level].size;
 	}
 
 	/* Note the required size in memory */