Automatic display dimming
Windows automatically reduces the brightness level of an integrated display after a period of user inactivity. The functionality of this feature is configured with a set of power policy settings.
The primary setting for this feature is the dim display after setting, which is described in Table 1 Dim display time-out setting. This setting configures the amount of user inactivity after which the system automatically reduces the display brightness level.
Table 1 Dim display time-out setting
| Name | Dim display after |
|---|---|
| Description | The period of inactivity before the display brightness is automatically reduced. This setting applies only to portable computers that support Windows control of the brightness level of an integrated display device. |
| GUID | 17aaa29b-8b43-4b94-aafe-35f64daaf1ee |
| PowerCfg Alias | VIDEODIM |
| Minimum Value | 0 (never automatically reduce display brightness) |
| Maximum Value | Maximum Integer |
| Label | Seconds |
| Hidden | No |
| Operating System Versions | Available in Windows 7 and later versions of Windows |
Windows automatically extends dim idle time-out based on user input activity. For example, if the display brightness level is dimmed because of user inactivity but user input is detected within five seconds of the brightness level transition, dim idle time-out period automatically doubles. The adjusted time-out value can be extended up to the display power-off time-out. The adjusted time-out value is temporary. It is automatically reset back to the dim idle time-out setting that is specified in the power policy after a successful dim transition in which no user input is detected immediately following the transition.
When the dim idle time-out expires, Windows changes the display brightness to the value specified in the dimmed display brightness setting. This setting is described in Table 2 Dimmed display brightness setting, which is by default set to 50%.
Starting in Windows 8, this setting represents a relative percentage. That is, when Windows decides to dim the display, the value of this setting is multiplied by the current display brightness (see Table 1 Display brightness setting in Display brightness) to arrive at the new actual display brightness. For example, if the system is in DC and the default DC brightness level is 40%, a 50% dim would change the actual brightness level to 20%. The system manufacturer should customize these default values based on the system's display technology and relative brightness levels.
Table 2 Dimmed display brightness setting
| Name | Dimmed display brightness |
|---|---|
| Description | Reduced display brightness level after the dim idle time-out (dim display after) has been reached. The value of this setting is multiplied by the current display brightness to arrive at the new actual display brightness. This setting applies only to portable computers that support Windows control of the brightness level of an integrated display device. |
| GUID | f1fbfde2-a960-4165-9f88-50667911ce96 |
| PowerCfg Alias | - |
| Minimum Value | 0 |
| Maximum Value | 100 |
| Label | % (Percentage) |
| Hidden | No |
| Operating System Versions | Available in Windows 7 and later versions of Windows (note the modified behavior in Windows 8). |
Table 3 Increase dim timeout setting
| Name | Increase adaptive timeout by |
|---|---|
| Description | Reduced display brightness level after the dim idle time-out (dim display after) has been reached. The value The percentage of the dim idle time-out value by which to automatically increase the dim idle time-out value if user annoyance is detected. This setting applies only to portable computers that support Windows control of the brightness level of an integrated display device. Usually, this setting should not be changed from the default value. |
| GUID | eed904df-b142-4183-b10b-5a1197a37864 |
| PowerCfg Alias | VIDEOADAPTINC |
| Minimum Value | 0 (do not automatically extend the dim idle time-out when user annoyance is detected) |
| Maximum Value | 100 |
| Label | % (Percentage) |
| Hidden | Yes |
| Operating System Versions | Available in Windows 7 and later versions of Windows. |
Table 4 Dim annoyance time-out setting
| Name | Increase adaptive timeout by |
|---|---|
| Description | The user annoyance detection threshold. This setting specifies the duration between automatic display dimming and user input to consider the automatic display brightness level reduction an annoyance to the user. This setting applies only to portable computers that support Windows's control of the brightness level of an integrated display device. Usually, this setting should not be changed from the default value. |
| GUID | 82dbcf2d-cd67-40c5-bfdc-9f1a5ccd4663 |
| PowerCfg Alias | VIDEOANNOY |
| Minimum Value | 0 (do not turn off display) |
| Maximum Value | Maximum Integer |
| Label | Seconds |
| Hidden | No |
| Operating System Versions | Available in Windows 7 and later versions of Windows. |