Have we ever found that a game didn’t work well at one screen resolution and we were forced to use a lower one or did we just see how the one we use to work with isn’t good enough and we changed it to another one that is more comfortable for our eyes.
Whatever the situation, you will often have noticed that a resolution change does not happen automatically and that there is some delay in its appearance. That is, we don’t see the change from frame to frame, but we see a fade to black, and then see how our monitor displays the new resolution. Therefore, the moment this change occurs, the entire video system shuts down completely to restart under the new settings.
But, how are these parameters transmitted between the graphics card and the screen, how does our PC know which screen we have connected it to and how it works? The answer is simple, apart from the video cable
The origins of DisplayID
The origins of DisplayID lie in its direct predecessor, called EDID or Extended Data Display Identification. A standard that has been defined by VESA, the organization in charge of giving standards related to screens. It must be taken into account that in the case of computer screens, and since the era of VGA screens, we have had a large number of computer screens of all sizes or resolutions.
The first version of EDID was released in 1994, in the initial version of the DCC standard and was based on a change in the use of pins 4, 11, 12 and 15. Where before the implementation of EDID, these connectors from the popular analog video connector have been used to set different resolutions. With the advent of the Display Data Channel, pins 9, 12, and 15 were defined as the communication method for sending a collection of metadata up to 128 bytes, which includes monitor information such as the following:
- ID associated with the manufacturer.
- The serial number of the monitor.
- Its date of manufacture.
- The product identifier
- The type of video output
- screen resolution
- Supported color space
The EDID standard also evolved with video connectors and with the advent of LCD monitors and digital video connectors it was integrated into the already forgotten DVI port, the popular HDMI and also early versions of DisplayPort in the form of the pin defined as SDA.
The arrival of DisplayID
In December 2007, VESA decided to make a clean sweep to create what was originally to be the second generation EDID, which expanded the metadata table from 128 bytes to 256 bytes and was dubbed DisplayID, but broke backwards compatibility with its predecessor.
The difference between DisplayID and EDID is that the information blocks that contain the metadata are defined in blocks, they can have a variable size of up to 256 bytes. Thus, if it is necessary to integrate a new screen technology into the standard, it suffices to extend the content on the corresponding block, each defined by a unique label.
This added support for new screen types, new refresh rates, more resolutions and new screen technologies without being limited to just 128 bytes of information to define characteristics of the screen that the EDID had.
Where is it used?
If you have a device that currently has a display of any type, be very clear that DisplayID metadata sent over the video connection will be used. Let’s not forget that each screen contains a microcontroller responsible for receiving the video signal and controlling its display on the screen.
Therefore, it is not only found in the world of PCs, but also in mobile phones, video game consoles and in any device that uses a screen to communicate visual information to the user, regardless of the relationship that they maintain among themselves. DisplayID is therefore a necessary standard so that the use of screens is automatic and does not require configuration, i.e. log in and go.
In other words, if this standard did not exist, something as simple and necessary as connecting an external display would become a real hell that would be expensive for us to solve because we would not be able to see the images on the new monitor, which would require the use of another to be able to configure it.
Why does the material have to identify itself?
We must start from the fact that all the components connected through the PCI Express bays have the PCI-ID, whereas if we talk about connections through USB, this is where the USB-ID makes its appearance. The identification codes of the various peripherals of a computer are used to detect plug and play or plug and play. As soon as new hardware is detected, the operating system asks for the ID and searches for its driver among the system files or the Internet driver repository corresponding to the ID of that particular hardware.
Displays, on the other hand, use video connectors such as DisplayPort, HDMI, DVI, VGA and many other industry standards, however, it is important that our PC’s graphics hardware has the ability to communicate with any type of screen that you can connect to and work well with. Thus, the metadata connection, which is DisplayID, is also crucial when we have special cases where the communication between the two ends is not completely smooth or image artifacts occur.
Table of Contents
