I successfully installed Linux Mint 17.3 Cinnamon 64-bit on my old iMac 21.5 (late 2009).When booting into Linux Mint (Live USB or installed version) there is still a bug: The built-in display shows 4 screens (all of them are the same, just as the Mirroring option). When I attach an external monitor, the built-in one has still this issue, but the external one works perfectly fine.Any advices on how to solve this problem?
Built-in display issue - Linux Mint on iMac (late 2009)
linux;linux mint;monitors;display