My MacBook pro has developed the (discrete) ATI graphics fault. It's a late 2011 MacBook pro with both intel HD and additional ATI card built in. It has all the signs of the graphics card fault as the screen corrupts and system reboots when it needs to use the ATI card. Seems to be well documented and accepted as a known fault by Apple The gfxcardstatus app used to let you control it, now it cannot do so under Yosemite as the OS overrules it. I'm waiting to get it seen by apple, but in the mean time is there any way I can get the MacBook to disable the ATI card so that certain apps don't activate it and cause the reboot?