I'm unable to get my MacBook Pro to connect to my LG monitor via a KVM switch. A direct connection to the monitor works. The KVM does report the correct EDID information (as testing via Linux), but on OSX I can't see the display at all when connected this way.
macOS Sierra 10.12.15
DisplayPort->DVI Adapter (Apple)
LG W2443T
UNICLASS 4-Port DVI
I've used the command ioreg -lw0 -r -c "IODisplayConnect" to get information about the connected monitors. When connected directly I see both monitors. Via the KVM only one appears.
Is there some way to force the OS to find/use this external second monitor.
The KVM shows a connection to the MacBook (blinking light stops blinking). The keyboard/mouse connection work fine.
Best Answer
The issue appears to be an incompatibility in the DVI Cable types. I was using a DVI-D dual link cable and swapped it out for a DVI-D Single link one. My monitor is connected to the KVM also with a DVI-D single link.
I presume somehow the MacBook was detecting dual link support, though the KVM does not support it I believe. By switching the cable I guess I forced the entire chain to be recognized as single link only.