Comment 2 for bug 1217364

StacktraceTop:
 damage (pixmap=<optimized out>, pixmap=<optimized out>, region=0x0, priv=0x0) at ../../../src/sna/sna_dri.c:489
 __sna_dri_copy_region (sna=sna@entry=0x7f96fed96000, draw=draw@entry=0x7f96ffe77c30, region=region@entry=0x0, src=src@entry=0x7f97003b2570, dst=dst@entry=0x7f9700120490, sync=sync@entry=false) at ../../../src/sna/sna_dri.c:774
 sna_dri_schedule_swap (client=0x7f97000c65b0, draw=0x7f96ffe77c30, front=0x7f9700120490, back=0x7f97003b2570, target_msc=0x7fff9078a938, divisor=<optimized out>, remainder=0, func=0x7f96ff00d3f0 <DRI2SwapEvent>, data=0x7f96ffe77c30) at ../../../src/sna/sna_dri.c:2074
 DRI2SwapBuffers (client=client@entry=0x7f97000c65b0, pDraw=0x7f96ffe77c30, target_msc=0, divisor=0, remainder=<optimized out>, swap_target=swap_target@entry=0x7fff9078a938, func=func@entry=0x7f96ff00d3f0 <DRI2SwapEvent>, data=0x7f96ffe77c30) at ../../../../hw/xfree86/dri2/dri2.c:1178
 ProcDRI2SwapBuffers (client=0x7f97000c65b0) at ../../../../hw/xfree86/dri2/dri2ext.c:413