Coreboot Options

Until recently, coreboot was using a custom, "home-made" config system. For some time you can look at the old list of options.

The new config system is Kconfig (a.k.a. "make menuconfig"), the well-known system as also used by the Linux kernel, busybox and a various other projects.

This is an automatically generated list of coreboot kconfig compile-time options.

Last update: 2010/02/09 15:05:25. (r5100)

Option	Source	Format	Short Description	Description
Menu: General setup
EXPERT	toplevel	bool	Expert mode	This allows you to select certain advanced configuration options. Warning: Only enable this option if you really know what you are doing! You have been warned!
LOCALVERSION	toplevel	string	Local version string	Append an extra string to the end of the coreboot version. This can be useful if, for instance, you want to append the respective board's hostname or some other identifying string to the coreboot version number, so that you can easily distinguish boot logs of different boards from each other.
Menu: Mainboard
BOARD_ROMSIZE_KB_4096	mainboard	bool	ROM chip size	Select the size of the ROM chip you intend to flash coreboot on. The build system will take care of creating a coreboot.rom file of the matching size.
COREBOOT_ROMSIZE_KB_128	mainboard	bool	128 KB	Choose this option if you have a 128 KB ROM chip.
COREBOOT_ROMSIZE_KB_256	mainboard	bool	256 KB	Choose this option if you have a 256 KB ROM chip.
COREBOOT_ROMSIZE_KB_512	mainboard	bool	512 KB	Choose this option if you have a 512 KB ROM chip.
COREBOOT_ROMSIZE_KB_1024	mainboard	bool	1024 KB (1 MB)	Choose this option if you have a 1024 KB (1 MB) ROM chip.
COREBOOT_ROMSIZE_KB_2048	mainboard	bool	2048 KB (2 MB)	Choose this option if you have a 2048 KB (2 MB) ROM chip.
COREBOOT_ROMSIZE_KB_4096	mainboard	bool	4096 KB (4 MB)	Choose this option if you have a 4096 KB (4 MB) ROM chip.
Menu: Chipset
		(comment)		CPU
SMP	cpu	bool		This option is used to enable certain functions to make coreboot work correctly on symmetric multi processor (SMP) systems.
VAR_MTRR_HOLE	cpu	bool		Unset this if you don't want the MTRR code to use subtractive MTRRs
		(comment)		Northbridge
		(comment)		Southbridge
Menu: AMD Geode GX1 video support
		(comment)		Super I/O
		(comment)		Devices
VGA_BRIDGE_SETUP	devices	bool	Setup bridges on path to VGA adapter	Allow bridges to set up legacy decoding ranges for VGA. Don't disable this unless you're sure you don't want the briges setup for VGA.
VGA_ROM_RUN	devices	bool	Run VGA option ROMs	Execute VGA option ROMs, if found. This is required to enable PCI/AGP/PCI-E video cards.
PCI_ROM_RUN	devices	bool	Run non-VGA option ROMs	Execute non-VGA PCI option ROMs, if found. Examples include IDE/SATA controller option ROMs and option ROMs for network cards (NICs).
PCI_OPTION_ROM_RUN_REALMODE	devices	bool	Real mode	If you select this option, PCI option ROMs will be executed natively on the CPU in real mode. No CPU emulation is involved, so this is the fastest, but also the least secure option. (only works on x86/x64 systems)
PCI_OPTION_ROM_RUN_X86EMU	devices	bool	x86emu	If you select this option, the x86emu CPU emulator will be used to execute PCI option ROMs. When choosing this option, x86emu will pass through all hardware accesses to memory and IO devices to the underlying memory and IO addresses. While this option prevents option ROMs from doing dirty tricks with the CPU (such as installing SMM modules or hypervisors), they can still access all devices in the system. Choosing x86emu, option ROM execution is slower than native execution in real mode, but faster than the full system emulation YABEL This is the default choice for non-x86 systems.
PCI_OPTION_ROM_RUN_YABEL	devices	bool	YABEL	If you select this option, the YABEL system emulator will be used to execute PCI option ROMs. YABEL consists of two parts: It uses x86emu for the CPU emulation and additionally provides a PC system emulation that filters bad device and memory access (such as PCI config space access to other devices than the initialized one). This option best prevents option ROMs from doing dirty tricks with the system (such as installing SMM modules or hypervisors), but it is also significantly slower than the other option ROM initialization methods.
YABEL_DEBUG_FLAGS	devices	hex	Hex value for YABEL debug flags	See debug.h for values 0 is no debug output, 0x31ff is _verbose_.
Menu: Console options
CONSOLE_SERIAL8250	console	bool	Serial port console output	Send coreboot debug output to a serial port console.
CONSOLE_SERIAL_COM1	console	bool	COM1/ttyS0, I/O port 0x3f8	Serial console on COM1/ttyS0 at I/O port 0x3f8.
CONSOLE_SERIAL_COM2	console	bool	COM2/ttyS1, I/O port 0x2f8	Serial console on COM2/ttyS1 at I/O port 0x2f8.
CONSOLE_SERIAL_COM3	console	bool	COM3/ttyS2, I/O port 0x3e8	Serial console on COM3/ttyS2 at I/O port 0x3e8.
CONSOLE_SERIAL_COM4	console	bool	COM4/ttyS3, I/O port 0x2e8	Serial console on COM4/ttyS3 at I/O port 0x2e8.
TTYS0_BASE	console	hex		Map the COM port names to the respective I/O port.
CONSOLE_SERIAL_115200	console	bool	115200	Set serial port Baud rate to 115200.
CONSOLE_SERIAL_57600	console	bool	57600	Set serial port Baud rate to 57600.
CONSOLE_SERIAL_38400	console	bool	38400	Set serial port Baud rate to 38400.
CONSOLE_SERIAL_19200	console	bool	19200	Set serial port Baud rate to 19200.
CONSOLE_SERIAL_9600	console	bool	9600	Set serial port Baud rate to 9600.
TTYS0_BAUD	console	int		Map the Baud rates to an integer.
SERIAL_POST	console	bool	Show POST codes on the serial port console	If enabled, coreboot will additionally print POST codes (which are usually displayed using a so-called "POST card" ISA/PCI/PCI-E device) on the serial console.
USBDEBUG_DIRECT	console	bool	USB 2.0 EHCI debug dongle support	This option allows you to use a so-called USB EHCI Debug device to retrieve the coreboot debug messages (instead, or in addition to, a serial port). This feature is NOT supported on all chipsets in coreboot! It also requires a USB2 controller which supports the EHCI Debug Port capability. Controllers which are known to work: 10b9:5239 ALi Corporation USB 2.0 (USB PCI card) 8086:24cd Intel ICH4/ICH4-M 8086:24dd Intel ICH5 8086:265c Intel ICH6 8086:268c Intel 631xESB/632xESB/3100 8086:27cc Intel ICH7 8086:2836 Intel ICH8 8086:283a Intel ICH8 8086:293a Intel ICH9 10de:0088 NVIDIA MCP2A 10de:005b NVIDIA CK804 10de:026e NVIDIA MCP51 10de:036d NVIDIA MCP55 10de:03f2 NVIDIA MCP61 1002:4386 ATI/AMD SB600 1106:3104 VIA VX800 See http://www.coreboot.org/EHCI_Debug_Port for an up-to-date list.
CONSOLE_VGA_ONBOARD_AT_FIRST	console	bool	Use onboard VGA as primary video device	If not selected, the last adapter found will be used.
MAXIMUM_CONSOLE_LOGLEVEL_8	console	bool	8: SPEW	Way too many details.
MAXIMUM_CONSOLE_LOGLEVEL_7	console	bool	7: DEBUG	Debug-level messages.
MAXIMUM_CONSOLE_LOGLEVEL_6	console	bool	6: INFO	Informational messages.
MAXIMUM_CONSOLE_LOGLEVEL_5	console	bool	5: NOTICE	Normal but significant conditions.
MAXIMUM_CONSOLE_LOGLEVEL_4	console	bool	4: WARNING	Warning conditions.
MAXIMUM_CONSOLE_LOGLEVEL_3	console	bool	3: ERR	Error conditions.
MAXIMUM_CONSOLE_LOGLEVEL_2	console	bool	2: CRIT	Critical conditions.
MAXIMUM_CONSOLE_LOGLEVEL_1	console	bool	1: ALERT	Action must be taken immediately.
MAXIMUM_CONSOLE_LOGLEVEL_0	console	bool	0: EMERG	System is unusable.
MAXIMUM_CONSOLE_LOGLEVEL	console	int		Map the log level config names to an integer.
DEFAULT_CONSOLE_LOGLEVEL_8	console	bool	8: SPEW	Way too many details.
DEFAULT_CONSOLE_LOGLEVEL_7	console	bool	7: DEBUG	Debug-level messages.
DEFAULT_CONSOLE_LOGLEVEL_6	console	bool	6: INFO	Informational messages.
DEFAULT_CONSOLE_LOGLEVEL_5	console	bool	5: NOTICE	Normal but significant conditions.
DEFAULT_CONSOLE_LOGLEVEL_4	console	bool	4: WARNING	Warning conditions.
DEFAULT_CONSOLE_LOGLEVEL_3	console	bool	3: ERR	Error conditions.
DEFAULT_CONSOLE_LOGLEVEL_2	console	bool	2: CRIT	Critical conditions.
DEFAULT_CONSOLE_LOGLEVEL_1	console	bool	1: ALERT	Action must be taken immediately.
DEFAULT_CONSOLE_LOGLEVEL_0	console	bool	0: EMERG	System is unusable.
DEFAULT_CONSOLE_LOGLEVEL	console	int		Map the log level config names to an integer.
HAVE_OPTION_TABLE	toplevel	bool		This variable specifies whether a given board has a cmos.layout file containing NVRAM/CMOS bit definitions. It defaults to 'y' but can be changed to 'n' in mainboard/*/Kconfig.
VGA	toplevel	bool		Build board-specific VGA code.
GFXUMA	toplevel	bool		Enable Unified Memory Architecture for graphics.
HAVE_LOW_TABLES	toplevel	bool		This Option is unused in the code. Since two boards try to set it to 'n', they may be broken. We either need to make the option useful or get rid of it. The broken boards are: asus/m2v-mx_se supermicro/h8dme
HAVE_HIGH_TABLES	toplevel	bool		This variable specifies whether a given northbridge has high table support. It is set in northbridge/*/Kconfig. Whether or not the high tables are actually written by coreboot is configurable by the user via WRITE_HIGH_TABLES.
HAVE_ACPI_TABLES	toplevel	bool		This variable specifies whether a given board has ACPI table support. It is usually set in mainboard/*/Kconfig. Whether or not the ACPI tables are actually generated by coreboot is configurable by the user via GENERATE_ACPI_TABLES.
HAVE_MP_TABLE	toplevel	bool		This variable specifies whether a given board has MP table support. It is usually set in mainboard/*/Kconfig. Whether or not the MP table is actually generated by coreboot is configurable by the user via GENERATE_MP_TABLE.
HAVE_PIRQ_TABLE	toplevel	bool		This variable specifies whether a given board has PIRQ table support. It is usually set in mainboard/*/Kconfig. Whether or not the PIRQ table is actually generated by coreboot is configurable by the user via GENERATE_PIRQ_TABLE.
Menu: System tables
GENERATE_ACPI_TABLES	toplevel	bool	Generate ACPI tables	Generate ACPI tables for this board. If unsure, say Y.
GENERATE_MP_TABLE	toplevel	bool	Generate an MP table	Generate an MP table (conforming to the Intel MultiProcessor specification 1.4) for this board. If unsure, say Y.
GENERATE_PIRQ_TABLE	toplevel	bool	Generate a PIRQ table	Generate a PIRQ table for this board. If unsure, say Y.
Menu: Payload
PAYLOAD_NONE	toplevel	bool	None	Select this option if you want to create an "empty" coreboot ROM image for a certain mainboard, i.e. a coreboot ROM image which does not yet contain a payload. For such an image to be useful, you have to use 'cbfstool' to add a payload to the ROM image later.
PAYLOAD_ELF	toplevel	bool	An ELF executable payload	Select this option if you have a payload image (an ELF file) which coreboot should run as soon as the basic hardware initialization is completed. You will be able to specify the location and file name of the payload image later.
FALLBACK_PAYLOAD_FILE	toplevel	string	Payload path and filename	The path and filename of the ELF executable file to use as payload.
COMPRESSED_PAYLOAD_LZMA	toplevel	bool	Use LZMA compression for payloads	In order to reduce the size payloads take up in the ROM chip coreboot can compress them using the LZMA algorithm.
Menu: VGA BIOS
VGA_BIOS	toplevel	bool	Add a VGA BIOS image	Select this option if you have a VGA BIOS image that you would like to add to your ROM. You will be able to specify the location and file name of the image later.
FALLBACK_VGA_BIOS_FILE	toplevel	string	VGA BIOS path and filename	The path and filename of the file to use as VGA BIOS.
FALLBACK_VGA_BIOS_ID	toplevel	string	VGA device PCI IDs	The comma-separated PCI vendor and device ID that would associate your VGA BIOS to your video card. Example: 1106,3230 In the above example 1106 is the PCI vendor ID (in hex, but without the "0x" prefix) and 3230 specifies the PCI device ID of the video card (also in hex, without "0x" prefix).
Menu: Debugging
GDB_STUB	toplevel	bool	GDB debugging support	If enabled, you will be able to set breakpoints for gdb debugging. See src/arch/i386/lib/c_start.S for details.