DXGK_BRIGHTNESS_SET callback function
Description
The DxgkDdiSetBrightness function sets a new brightness level.
Parameters
Context [in]
A handle to a context block that is associated with a display adapter. The display miniport driver's DxgkDdiAddDevice function previously provided this handle to the Microsoft DirectX graphics kernel subsystem.
Brightness [in]
The brightness level value to set.
Return value
DxgkDdiSetBrightness returns STATUS_SUCCESS if it succeeds in setting a new brightness level. Otherwise, it returns one of the error codes defined in Ntstatus.h.
The monitor driver calls the display miniport driver's DxgkDdiSetBrightness function to change the brightness level of the integrated display panel for the following reasons:
- Notifications from the Device Power Policy Engine (DPPE) indicate that either the current policy is modified or a new policy takes effect. A new DPPE policy takes effect on system start, resume, and user switch, as well as when the power source is changed.
- The preferred way for user-mode clients to control brightness is through Windows Management Instrumentation (WMI). The monitor driver implements the WMI brightness controls that select a brightness level or revert the brightness level to the level that was selected by the currently active DPPE policy. The WMI method to select a brightness level overrides the current DPPE policy level until any change in DPPE policy occurs. When DPPE policy changes, the new DPPE level is set.
- For compatibility with the Windows 2000 Display Driver Model, the monitor driver implements IOCTL_VIDEO_SET_DISPLAY_BRIGHTNESS as an alternative way for user-mode clients to control brightness. A call to IOCTL_VIDEO_SET_DISPLAY_BRIGHTNESS is handled the same way as the WMI brightness control that selects a brightness level.
- The monitor driver interprets brightness hot-key notifications from the Advanced Configuration and Power Interface (ACPI) driver as user requests to change the current brightness level. As with the WMI and IOCTL user-mode interfaces, a change in brightness level that is triggered by a hot-key notification overrides the current DPPE policy and stays in effect until DPPE policy requests that the brightness value is set again.
DxgkDdiSetBrightness should be made pageable.
See also
DxgkDdiAddDevice
IOCTL_VIDEO_SET_DISPLAY_BRIGHTNESS
