Comment 2 for bug 1494488

StacktraceTop:
 dixGetPrivate (key=0x55a03f199ae0 <rrPrivKeyRec>, privates=0x3d0) at ../../include/privates.h:137
 dixLookupPrivate (key=0x55a03f199ae0 <rrPrivKeyRec>, privates=0x3d0) at ../../include/privates.h:167
 RRTellChanged (pScreen=pScreen@entry=0x55a04004c210) at ../../randr/randr.c:576
 sna_mode_discover (sna=sna@entry=0x7fde4864e000) at ../../../src/sna/sna_display.c:4870
 __sna_crtc_set_mode (crtc=<optimized out>) at ../../../src/sna/sna_display.c:2624