Apple computers: Black screen or unresponsive Mini DisplayPort display after sleep
In certain circumstances you may notice a black screen after waking your computer from sleep. The computer may also appear to be unresponsive when the black screen appears.
You may notice this with Target Display Mode or when you use at least two Mini DisplayPort devices.
Use only VESA 1.1a compliant Mini DisplayPort to DisplayPort adapters. Check with the manufacturer of the cable or consult the documentation included with it to determine if the cable is VESA 1.1a compliant.
Certain cables advertised as being VESA 1.1a compliant may contain a construction issue that may result in the DisplayPort power pins at either end of the cable shorting together. VESA 1.1a compliant cables must isolate the DisplayPort power pins at either end of the cable.
To learn more about the VESA 1.1a DisplayPort Interoperability Guidelines, visit www.vesa.org.