/*
<rdar://problem/33240449> 17A306d : Coin Flip app and gfxCardStatus go not responding, stuck in IOFramebuffer::_extEntry()
When extCopySharedCursor() was introduced, the usage of extEntry/extExit was added.
For now, comment these out and return to the previous functionality and
lack-of-locking while maintaining the structure and usage of extCopySharedCursor().
*/
I do not know if this will influence any version of gfxCardStatus in High Sierra 10.13.
High Sierra - 10.13 - IOFramebuffer.cpp - mentions gfxCardStatus:
https://opensource.apple.com/source/IOGraphics/IOGraphics-517.17/IOGraphicsFamily/IOFramebuffer.cpp.auto.html