The drawing error is an issue in the output. The "self-copy" and "subsurface" I mentioned are the cases in cairo/test/: self-copy.c and subsurface.c. So you can check the output pictures, which are incorrect. These cases use target surface as their source surface at the same time, which cause the render output incorrect. (When you bind one image from a texture to an FBO, and If you do try to read and write to the same image, you get undefined results.) <div class="gmail_quote">2012/1/11 Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>> <blockquote style="BORDER-LEFT:#ccc 1px solid;MARGIN:0px 0px 0px 0.8ex;PADDING-LEFT:1ex" class="gmail_quote"> <div class="im">On Wed, 11 Jan 2012 17:03:46 +0800, Chuanbo Weng <<a href="mailto:strgnm@gmail.com">strgnm@gmail.com</a>> wrote: > We have to create a new surface to avoid drawing error when the source > and destination is the same surface. Also, we should create a new texture > surface when the source surface type is cairo_glx_surface_t. This fix > issue in self-copy, subsurface and subsurface-modify-child test case. </div>What's the drawing error? A GL error? An issue in the output? Due to its render roots, self-copy is undefined in the Cairo API so unless this prevents an explicit error against the GL spec, I'm not going to accept it without the larger issue (of defining self-copy) being addressed. -Chris -- Chris Wilson, Intel Open Source Technology Centre </blockquote></div>