This exists in HDMI and I'm pretty sure it has to exist in newer standards. Generally the problem is that figuring out that something is plugged is not enough,

This exists in HDMI and I'm pretty sure it has to exist in newer standards. Generally the problem is that figuring out that something is plugged is not enough, you also need to know what is plugged, what resolutions it supports etc... I don't know how DP does it but previously there was a good old I2C link in the cable that was used to figure out what the screen supported[1]. You only needed an I2C EPROM on the other hand containing the various modes. Without this the computer on the other end can't really prepare itself properly, preallocate the framebuffers etc... Since the EPROM requires very little energy it might even work if the monitor is not powered, just using the +5V coming from the HDMI cable. [1] https://en.wikipedia.org/wiki/Display_Data_Channel https://en.wikipedia.org/wiki/Display_Data_Channel