I have a 15" MacBook Pro with Retina Display and a ShiMian QH270-IPSMS monitor (2560×1440).
The first pitfall I ran across when setting this up was that the HDMI port doesn't support my display's resolution. Instead, I am using a Monoprice Mini DisplayPort to DVI Dual Link adapter, which supports the display's full resolution at 60 Hz.
However, when my computer sleeps the displays to save power (or I press ⌃+⇧+⏏), and I reawaken it, suddenly my external monitor is at a very low resolution (640×480?) and the laptop's display is black. With full sleep (or ⌥+⌘+⏏) the problem usually does not occur, although I have seen it occur a couple times. Whenever it happens I can put the computer to sleep and wake it up again and it will most often return to the normal 2560×1440 resolution.
- I thought it might be because the adapter is USB powered from my computer, but I plugged it into a powered external USB hub and that makes no difference.
- I tried resetting PRAM and that didn't help either.
- I previously installed SwitchResX when attempting to get the display's full resolution working via HDMI; this could perhaps affect what's going on, but I did fully uninstall it so I doubt it's causing problems.
Has anyone seen this behavior before, or might know what's going on or how to fix it?