vesa: live BIOS patching for Intel video devices

The VESA standard does not define any way for software to set a custom
video mode, which means normally we would be constrained to whichever
modes the video card manufacturer decided to provide. However, since we
run the BIOS in an emulated environment, it is possible (and even quite
easy) to patch it and inject any video mode we want, provided we know
the format to use and where to put the info in.

This approach was used in the NewOS VESA driver, as well as in
915resolution (a tool that predates the availability of native drivers
for Linux for Intel videocards). Later on it was also used in Chameleon
and Clover, bootloaders that are used for hackintoshes (running MacOS on
unsupported hardware).

This commit implements full support for Intel cards only, AMD and NVidia
will be added later (but there is preliminary code to detect them)

Change-Id: I2c528ba18b3863f486da694860a10761efcbfb3f
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4624
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: waddlesplash <[email protected]>

headers/private/graphics/vesa/vesa_info.h

@@ -23,8 +23,15 @@ struct vesa_mode {
 	uint8			bits_per_pixel;
 };
 
+enum bios_type_enum {
+	kUnknownBiosType = 0,
+	kIntelBiosType,
+	kNVidiaBiosType,
+	kAtomBiosType1,
+	kAtomBiosType2
+};
+
 struct vesa_shared_info {
-	int32			type;
 	area_id			mode_list_area;		// area containing display mode list
 	uint32			mode_count;
 	display_mode	current_mode;
@@ -40,6 +47,10 @@ struct vesa_shared_info {
 
 	edid1_info		edid_info;
 	bool			has_edid;
+	bios_type_enum	bios_type;
+	uint16			mode_table_offset;
+		// Atombios only: offset to the table of video modes in the bios, used for patching in
+		// extra video modes.
 	uint32			dpms_capabilities;
 };
 
@@ -53,6 +64,7 @@ enum {
 	VESA_GET_DPMS_MODE,
 	VESA_SET_DPMS_MODE,
 	VESA_SET_INDEXED_COLORS,
+	VESA_SET_CUSTOM_DISPLAY_MODE,
 
 	VGA_PLANAR_BLIT,
 };