EDID stands for Extended Display Identification Data. It is a data structure provided by a computer display to describe its capabilities to a graphics card. It is what enables a modern personal computer to know what kind of monitor is connected. EDID is defined by the Video Electronics Standards Association (VESA). The EDID includes manufacturer name, product type, phosphor or filter type, timings supported by the display, display size, luminance data and (for digital displays only) pixel mapping data.
The channel for transmitting the EDID from the display to the graphics card is usually the I²C bus. The combination of EDID and I²C is called the Display Data Channel (DDC). Before DDC and EDID were defined, there was no standard way for a graphics card to know what kind of display device it was connected to.
To light the single display device by EDID, the following per-conditions should be satisfied at the same time.
Currently, most display devices, including CRT, LCD panel, DVI, HDMI have EDID. Regarding to those display devices without EDID, the VIA driver will light them by the built-in timing.
For the VIA accelerated Linux graphics driver, the modeline settings have the first piority when lighting the display devices. Get more information about modeline settings from Part VI. Chapter 5. Modeline Support.
When using XRandR extension, each display device could be lighted by its EDID.
However, if you do not want to light the display device by its EDID, you can use the option below to disable it. In this case, the driver will light the device in a mandatory way. When using XRandR extension, this option should be added into the related Monitor section. (This option only supports CRT and DVI.)
It is not recommended to use this option. The display device can be damaged if the given mode is beyond its ablility.Option "NoDDCValue"