When Windows changes the display configuration between the available monitors on the system and the modes used, it communicates with the WDDM driver to enumerate all these possibilities so that it can provide a rich set of options to the user. However, because of the large number of combinations, this operation may take a long time. Therefore, the user may experience a black screen or an unresponsive mouse pointer for as long as 30 seconds before the image on the desktop is redrawn. The length of this delay increases with the use of larger monitors that are capable of including many modes, as reported in their EDID structures.
The driver can limit the number of modes that it supports, and this helps reduce the time required to complete enumeration of the mode sets. This is the recommended action to take if you decide that the display device enumeration delays are too lengthy.
Note Drivers can allow enumerations of larger mode sets or of all available modes if you need that flexibility for specific applications.
- The driver must enumerate the native resolutions for each of the connected displays.
- We recommend that the driver enumerate other lower resolutions that match the aspect ratio of the native resolution.
- We recommend that the driver enumerate a resolution of 1024 x 768 dots per inch (dpi), because this is a common resolution that's used by many applications.
- In duplicate mode, the driver must enumerate resolutions that are common to all the affected displays. At the very least, the driver must enumerate a 1024 x 768 resolution.
- We recommend that driver not enumerate any resolutions that are lower than 1024 x 768 dpi.
Note However, the following specs must be enumerated for backward-compatibility.
- 800 x 600 dpi
- 640 x 480 dpi
- 32 bits per pixel (bpp) and 0 rotation
You can also use a registry key to open more modes as necessary.
Article ID: 2742680 - Last Review: 7 Sep 2014 - Revision: 1