Waking up Dell P4317Q 43" Display after Mac Wakeup

EDID is the query and response the Mac sends and the display (if paying attention and not goofing off) responds with.

EDID overrides are how you can extend the capabilities of a particular display when the maker and Apple do not agree about what the 'stock' EDID response should mean. Hobbyists started looking into it to get high-resolution displays to respond like genuine Apple "retina" displays, with a high maximum resolution and 'Scaled' settings to make text appear readable.

to get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display.

This query is only sent at certain times:

• at startup

• at wake from sleep

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• on invoking Option-(Detect Display) button in Displays preferences

so try doing some of those things and see if the display comes alive.

Modern Displays with multiple ports are sometimes busy scanning the other ports, looking for an input, and miss the query from the Mac. They need to pay attention to the port you are actually using, or they will miss the query.

Some displays have On-Screen Display settings that can be used to tell the display a computer is attached on a certain port, or a certain port should be highest priority. Changing those may make your display more responsive.

Some displays include their own private "sleep" settings for the display alone. This can allow the display to enter its own sleep mode, on top of the Mac's not sending it data. A display that is sleeping on its own cannot respond to the Mac's query, and will stay dark.

There might be. What Mr. Bennet-Alder wrote is quite true, and yes, give those things a try. However, I should tell you that this is a somewhat common problem, at least between Mac's and Dell monitors, at least I've found it to be so. There is no need to email Dell, because they'll tell you they don't support Macs at all, not for anything, monitors, printers, whatever. Likewise, emailing Apple does no good because they might say it's Dell's problem, and in that, they are technically correct. So: I don't know of any utility that can simulate unplugging the cable and waking up the display. For me, I had to physically unplug the power cable to my Dell monitor once in a while to get it to wake up and work. Annoying to say the least. What worked for me was an EDID overrride for Dell Monitors on OS X. Don't ask me why or how it works, I just know that it did. Eventually I solved the problem by winning some money on a scratch card, selling the old monitor and buying a new LG monitor. I got lucky, I guess. Anyways, down to the fix: Go here for that:

https://embdev.net/topic/284710#3027030

and you'll have to disable SIP (system Integrity Protection)

and here's how (screenshot attached)

and yeah, that's all I got

jb