5F35h – Boot Display Device Hook

This hook allows the system BIOS to override the video display default setting. The graphics BIOS will set the returned video display during POST (power up initialization).

Note: This function is not entirely compatible with the Desktop and Mobile Video BIOS. The bits in CL have a configurable mapping to the Port Numbers as defined in Generating the Video Firmware. The assigned meanings used in the Desktop specification can be duplicated with a correct configuration. The values below are the default values if no “Common To Port” mapping is provided.

Calling Registers:

AX = 5F35h, Boot Display Device Hook

Return Registers:

AX = Return Status (function not supported if AL != 5Fh);

= 005Fh, Function supported and successful

= 015Fh, Function supported but failed

CL = Display Device Combination to boot (1 = Enable display, 0 = Disable display):

= 00h, VBIOS Default

Bit 7 - 6 = Reserved

Bit 5 = Port 5 (or common_to_port[5])

Bit 4 = Port 4 (or common_to_port[4])

Bit 3 = Port 3 (or common_to_port[3])

Bit 2 = Port 2 (or common_to_port[2])

Bit 1 = Port 1 (or common_to_port[1])

Bit 0 = Port 0 (or common_to_port[0])