PRE_CRTC_MODE_CHANGE (Function 28)

Call With

EBX: Contains a Windows VM Handle.

EBP: Points to the Window VM's Client Registers. Client registers may be used to pass any data between the display driver and the mini-VDD (besides Client EAX and Client EBX which contain the sub-function code for VDD_PRE_CRTC_MODE_CHANGE and VDD_POST_CRTC_MODE_CHANGE and the magic numbers respectively).

Return Values

Anything the display driver and mini-VDD agree upon.

Remarks

The Main VDD calls these routines when the display driver calls the Main VDD VDD_PRE_MODE_CHANGE and VDD_POST_MODE_CHANGE functions. If you look at the example display driver and the S3 or CIRRUS mini-VDD, you can see that these calls are mainly used to setup the monitor refresh rate prior to or after the display driver SetMode routine during Enable. However, these routines can be called for any convenient purpose similar to the REGISTER_DISPLAY_DRIVER function.