EBX: Contains a Windows VM Handle.
EBP: Points to the Windows VM's Client Registers.
Save anything that you use. You must not fail this call. If it is hooked, it must be implemented.
This function gives the mini-VDD the opportunity to save the VGA processor latches. The Main VDD goes through a lengthy process to save and restore the latches during 4 plane virtualization. Many new VGA cards can read the latches directly through CRTC port 22h and this routine gives them the opportunity to do so. If you implement this function (along with RESTORE_LATCHES), you need not implement SET_LATCH_BANK and RESET_LATCH_BANK. You should save the latches in the mini-VDD's CB data area.