NOTES (revision 10041e99a0c29c9f99c4148fc173bb12dd26aa8d) - OpenGrok cross reference for /freebsd/sys/i386/conf/NOTES

#
# NOTES -- Lines that can be cut/pasted into kernel and hints configs.
#
# This file contains machine dependent kernel configuration notes.  For
# machine independent notes, look in /sys/conf/NOTES.
#
# $FreeBSD$
#

#
# Enable the kernel DTrace hooks which are required to load the DTrace
# kernel modules.
#
options 	KDTRACE_HOOKS

# DTrace core
# NOTE: introduces CDDL-licensed components into the kernel
#device		dtrace

# DTrace modules
#device		dtrace_profile
#device		dtrace_sdt
#device		dtrace_fbt
#device		dtrace_systrace
#device		dtrace_prototype
#device		dtnfscl
#device		dtmalloc

# Alternatively include all the DTrace modules
#device		dtraceall


#####################################################################
# SMP OPTIONS:
#
# The apic device enables the use of the I/O APIC for interrupt delivery.
# The apic device can be used in both UP and SMP kernels, but is required
# for SMP kernels.  Thus, the apic device is not strictly an SMP option,
# but it is a prerequisite for SMP.
#
# Notes:
#
# HTT CPUs should only be used if they are enabled in the BIOS.  For
# the ACPI case, ACPI only correctly tells us about any HTT CPUs if
# they are enabled.  However, most HTT systems do not list HTT CPUs
# in the MP Table if they are enabled, thus we guess at the HTT CPUs
# for the MP Table case.  However, we shouldn't try to guess and use
# these CPUs if HTT is disabled.  Thus, HTT guessing is only enabled
# for the MP Table if the user explicitly asks for it via the
# MPTABLE_FORCE_HTT option.  Do NOT use this option if you have HTT
# disabled in your BIOS.
#
# IPI_PREEMPTION instructs the kernel to preempt threads running on other
# CPUS if needed.  Relies on the PREEMPTION option

# Mandatory:
device		apic			# I/O apic

# Optional:
options 	MPTABLE_FORCE_HTT	# Enable HTT CPUs with the MP Table
options 	IPI_PREEMPTION

#
# Watchdog routines.
#
options 	MP_WATCHDOG

# Debugging options.
#
options 	COUNT_XINVLTLB_HITS	# Counters for TLB events
options 	COUNT_IPIS		# Per-CPU IPI interrupt counters


#####################################################################
# CPU OPTIONS

#
# You must specify at least one CPU (the one you intend to run on);
# deleting the specification for CPUs you don't need to use may make
# parts of the system run faster.
#
cpu		I486_CPU
cpu		I586_CPU		# aka Pentium(tm)
cpu		I686_CPU		# aka Pentium Pro(tm)

#
# Options for CPU features.
#
# CPU_ATHLON_SSE_HACK tries to enable SSE instructions when the BIOS has
# forgotten to enable them.
#
# CPU_BLUELIGHTNING_3X enables triple-clock mode on IBM Blue Lightning
# CPU if CPU supports it.  The default is double-clock mode on
# BlueLightning CPU box.
#
# CPU_BLUELIGHTNING_FPU_OP_CACHE enables FPU operand cache on IBM
# BlueLightning CPU.  It works only with Cyrix FPU, and this option
# should not be used with Intel FPU.
#
# CPU_BTB_EN enables branch target buffer on Cyrix 5x86 (NOTE 1).
#
# CPU_CYRIX_NO_LOCK enables weak locking for the entire address space
# of Cyrix 6x86 and 6x86MX CPUs by setting the NO_LOCK bit of CCR1.
# Otherwise, the NO_LOCK bit of CCR1 is cleared.  (NOTE 3)
#
# CPU_DIRECT_MAPPED_CACHE sets L1 cache of Cyrix 486DLC CPU in direct
# mapped mode.  Default is 2-way set associative mode.
#
# CPU_DISABLE_5X86_LSSER disables load store serialize (i.e., enables
# reorder).  This option should not be used if you use memory mapped
# I/O device(s).
#
# CPU_ELAN enables support for AMDs ElanSC520 CPU.
#    CPU_ELAN_PPS enables precision timestamp code.
#    CPU_ELAN_XTAL sets the clock crystal frequency in Hz.
#
# CPU_ENABLE_LONGRUN enables support for Transmeta Crusoe LongRun
# technology which allows to restrict power consumption of the CPU by
# using group of hw.crusoe.* sysctls.
#
# CPU_FASTER_5X86_FPU enables faster FPU exception handler.
#
# CPU_GEODE is for the SC1100 Geode embedded processor.  This option
# is necessary because the i8254 timecounter is toast.
#
# CPU_I486_ON_386 enables CPU cache on i486 based CPU upgrade products
# for i386 machines.
#
# CPU_IORT defines I/O clock delay time (NOTE 1).  Default values of
# I/O clock delay time on Cyrix 5x86 and 6x86 are 0 and 7,respectively
# (no clock delay).
#
# CPU_L2_LATENCY specifies the L2 cache latency value.  This option is used
# only when CPU_PPRO2CELERON is defined and Mendocino Celeron is detected.
# The default value is 5.
#
# CPU_LOOP_EN prevents flushing the prefetch buffer if the destination
# of a jump is already present in the prefetch buffer on Cyrix 5x86(NOTE
# 1).
#
# CPU_PPRO2CELERON enables L2 cache of Mendocino Celeron CPUs.  This option
# is useful when you use Socket 8 to Socket 370 converter, because most Pentium
# Pro BIOSs do not enable L2 cache of Mendocino Celeron CPUs.
#
# CPU_RSTK_EN enables return stack on Cyrix 5x86 (NOTE 1).
#
# CPU_SOEKRIS enables support www.soekris.com hardware.
#
# CPU_SUSP_HLT enables suspend on HALT.  If this option is set, CPU
# enters suspend mode following execution of HALT instruction.
#
# CPU_UPGRADE_HW_CACHE eliminates unneeded cache flush instruction(s).
#
# CPU_WT_ALLOC enables write allocation on Cyrix 6x86/6x86MX and AMD
# K5/K6/K6-2 CPUs.
#
# CYRIX_CACHE_WORKS enables CPU cache on Cyrix 486 CPUs with cache
# flush at hold state.
#
# CYRIX_CACHE_REALLY_WORKS enables (1) CPU cache on Cyrix 486 CPUs
# without cache flush at hold state, and (2) write-back CPU cache on
# Cyrix 6x86 whose revision < 2.7 (NOTE 2).
#
# NO_F00F_HACK disables the hack that prevents Pentiums (and ONLY
# Pentiums) from locking up when a LOCK CMPXCHG8B instruction is
# executed.  This option is only needed if I586_CPU is also defined,
# and should be included for any non-Pentium CPU that defines it.
#
# NO_MEMORY_HOLE is an optimisation for systems with AMD K6 processors
# which indicates that the 15-16MB range is *definitely* not being
# occupied by an ISA memory hole.
#
# NOTE 1: The options, CPU_BTB_EN, CPU_LOOP_EN, CPU_IORT,
# CPU_LOOP_EN and CPU_RSTK_EN should not be used because of CPU bugs.
# These options may crash your system.
#
# NOTE 2: If CYRIX_CACHE_REALLY_WORKS is not set, CPU cache is enabled
# in write-through mode when revision < 2.7.  If revision of Cyrix
# 6x86 >= 2.7, CPU cache is always enabled in write-back mode.
#
# NOTE 3: This option may cause failures for software that requires
# locked cycles in order to operate correctly.
#
options 	CPU_ATHLON_SSE_HACK
options 	CPU_BLUELIGHTNING_3X
options 	CPU_BLUELIGHTNING_FPU_OP_CACHE
options 	CPU_BTB_EN
options 	CPU_DIRECT_MAPPED_CACHE
options 	CPU_DISABLE_5X86_LSSER
options 	CPU_ELAN
options 	CPU_ELAN_PPS
options 	CPU_ELAN_XTAL=32768000
options 	CPU_ENABLE_LONGRUN
options 	CPU_FASTER_5X86_FPU
options 	CPU_GEODE
options 	CPU_I486_ON_386
options 	CPU_IORT
options 	CPU_L2_LATENCY=5
options 	CPU_LOOP_EN
options 	CPU_PPRO2CELERON
options 	CPU_RSTK_EN
options 	CPU_SOEKRIS
options 	CPU_SUSP_HLT
options 	CPU_UPGRADE_HW_CACHE
options 	CPU_WT_ALLOC
options 	CYRIX_CACHE_WORKS
options 	CYRIX_CACHE_REALLY_WORKS
#options 	NO_F00F_HACK

# Debug options
options 	NPX_DEBUG	# enable npx debugging

#
# PERFMON causes the driver for Pentium/Pentium Pro performance counters
# to be compiled.  See perfmon(4) for more information.
#
options 	PERFMON


#####################################################################
# NETWORKING OPTIONS

#
# DEVICE_POLLING adds support for mixed interrupt-polling handling
# of network device drivers, which has significant benefits in terms
# of robustness to overloads and responsivity, as well as permitting
# accurate scheduling of the CPU time between kernel network processing
# and other activities.  The drawback is a moderate (up to 1/HZ seconds)
# potential increase in response times.
# It is strongly recommended to use HZ=1000 or 2000 with DEVICE_POLLING
# to achieve smoother behaviour.
# Additionally, you can enable/disable polling at runtime with help of
# the ifconfig(8) utility, and select the CPU fraction reserved to
# userland with the sysctl variable kern.polling.user_frac
# (default 50, range 0..100).
#
# Not all device drivers support this mode of operation at the time of
# this writing.  See polling(4) for more details.

options 	DEVICE_POLLING

# BPF_JITTER adds support for BPF just-in-time compiler.

options 	BPF_JITTER

# OpenFabrics Enterprise Distribution (Infiniband).
options 	OFED
options 	OFED_DEBUG_INIT

# Sockets Direct Protocol
options 	SDP
options 	SDP_DEBUG

# IP over Infiniband
options 	IPOIB
options 	IPOIB_DEBUG
options 	IPOIB_CM


#####################################################################
# CLOCK OPTIONS

# Provide read/write access to the memory in the clock chip.
device		nvram		# Access to rtc cmos via /dev/nvram


#####################################################################
# MISCELLANEOUS DEVICES AND OPTIONS

device		speaker		#Play IBM BASIC-style noises out your speaker
envvar		hint.speaker.0.at="isa"
envvar		hint.speaker.0.port="0x61"


#####################################################################
# HARDWARE BUS CONFIGURATION

#
# ISA bus
#
device		isa

#
# Options for `isa':
#
# AUTO_EOI_1 enables the `automatic EOI' feature for the master 8259A
# interrupt controller.  This saves about 0.7-1.25 usec for each interrupt.
# This option breaks suspend/resume on some portables.
#
# AUTO_EOI_2 enables the `automatic EOI' feature for the slave 8259A
# interrupt controller.  This saves about 0.7-1.25 usec for each interrupt.
# Automatic EOI is documented not to work for for the slave with the
# original i8259A, but it works for some clones and some integrated
# versions.
#
# MAXMEM specifies the amount of RAM on the machine; if this is not
# specified, FreeBSD will first read the amount of memory from the CMOS
# RAM, so the amount of memory will initially be limited to 64MB or 16MB
# depending on the BIOS.  If the BIOS reports 64MB, a memory probe will
# then attempt to detect the installed amount of RAM.  If this probe
# fails to detect >64MB RAM you will have to use the MAXMEM option.
# The amount is in kilobytes, so for a machine with 128MB of RAM, it would
# be 131072 (128 * 1024).
#
# BROKEN_KEYBOARD_RESET disables the use of the keyboard controller to
# reset the CPU for reboot.  This is needed on some systems with broken
# keyboard controllers.

options 	AUTO_EOI_1
#options 	AUTO_EOI_2

options 	MAXMEM=(128*1024)
#options 	BROKEN_KEYBOARD_RESET

#
# AGP GART support
device		agp

# AGP debugging.
options 	AGP_DEBUG


#####################################################################
# HARDWARE DEVICE CONFIGURATION

# To include support for VGA VESA video modes
options 	VESA

# Turn on extra debugging checks and output for VESA support.
options 	VESA_DEBUG

device		dpms		# DPMS suspend & resume via VESA BIOS

# x86 real mode BIOS emulator, required by atkbdc/dpms/vesa
options 	X86BIOS

#
# Hints for the non-optional Numeric Processing eXtension driver.
envvar		hint.npx.0.flags="0x0"
envvar		hint.npx.0.irq="13"

#
# `flags' for npx0:
#	0x01	don't use the npx registers to optimize bcopy.
#	0x02	don't use the npx registers to optimize bzero.
#	0x04	don't use the npx registers to optimize copyin or copyout.
# The npx registers are normally used to optimize copying and zeroing when
# all of the following conditions are satisfied:
#	I586_CPU is an option
#	the cpu is an i586 (perhaps not a Pentium)
#	the probe for npx0 succeeds
#	INT 16 exception handling works.
# Then copying and zeroing using the npx registers is normally 30-100% faster.
# The flags can be used to control cases where it doesn't work or is slower.
# Setting them at boot time using hints works right (the optimizations
# are not used until later in the bootstrap when npx0 is attached).
# Flag 0x08 automatically disables the i586 optimized routines.
#

#
# Optional devices:
#

# PS/2 mouse
device		psm
envvar		hint.psm.0.at="atkbdc"
envvar		hint.psm.0.irq="12"

# Options for psm:
options 	PSM_HOOKRESUME		#hook the system resume event, useful
					#for some laptops
options 	PSM_RESETAFTERSUSPEND	#reset the device at the resume event

# The keyboard controller; it controls the keyboard and the PS/2 mouse.
device		atkbdc
envvar		hint.atkbdc.0.at="isa"
envvar		hint.atkbdc.0.port="0x060"

# The AT keyboard
device		atkbd
envvar		hint.atkbd.0.at="atkbdc"
envvar		hint.atkbd.0.irq="1"

# Options for atkbd:
options 	ATKBD_DFLT_KEYMAP	# specify the built-in keymap
makeoptions	ATKBD_DFLT_KEYMAP=fr.dvorak

# `flags' for atkbd:
#       0x01    Force detection of keyboard, else we always assume a keyboard
#       0x02    Don't reset keyboard, useful for some newer ThinkPads
#	0x03	Force detection and avoid reset, might help with certain
#		dockingstations
#       0x04    Old-style (XT) keyboard support, useful for older ThinkPads

# Video card driver for VGA adapters.
device		vga
envvar		hint.vga.0.at="isa"

# Options for vga:
# Try the following option if the mouse pointer is not drawn correctly
# or font does not seem to be loaded properly.  May cause flicker on
# some systems.
options 	VGA_ALT_SEQACCESS

# If you can dispense with some vga driver features, you may want to
# use the following options to save some memory.
#options 	VGA_NO_FONT_LOADING	# don't save/load font
#options 	VGA_NO_MODE_CHANGE	# don't change video modes

# Older video cards may require this option for proper operation.
options 	VGA_SLOW_IOACCESS	# do byte-wide i/o's to TS and GDC regs

# The following option probably won't work with the LCD displays.
options 	VGA_WIDTH90		# support 90 column modes

# Debugging.
options 	VGA_DEBUG

# vt(4) drivers.
device		vt_vga
device		vt_vbefb

# Linear framebuffer driver for S3 VESA 1.2 cards. Works on top of VESA.
device		s3pci

# 3Dfx Voodoo Graphics, Voodoo II /dev/3dfx CDEV support.  This will create
# the /dev/3dfx0 device to work with glide implementations.  This should get
# linked to /dev/3dfx and /dev/voodoo.  Note that this is not the same as
# the tdfx DRI module from XFree86 and is completely unrelated.
#
# To enable Linuxulator support, one must also load linux.ko and tdfx_linux.ko.

device		tdfx			# Enable 3Dfx Voodoo support

options 	IOMMU			# Enable IOMMU support

#
# ACPI support using the Intel ACPI Component Architecture reference
# implementation.
#
# ACPI_DEBUG enables the use of the debug.acpi.level and debug.acpi.layer
# kernel environment variables to select initial debugging levels for the
# Intel ACPICA code.  (Note that the Intel code must also have USE_DEBUGGER
# defined when it is built).

device		acpi
options 	ACPI_DEBUG

# ACPI WMI Mapping driver
device		acpi_wmi

# ACPI Asus Extras (LCD backlight/brightness, video output, etc.)
device		acpi_asus

# ACPI Fujitsu Extras (Buttons)
device		acpi_fujitsu

# ACPI extras driver for HP laptops
device		acpi_hp

# ACPI extras driver for IBM laptops
device		acpi_ibm

# ACPI Panasonic Extras (LCD backlight/brightness, video output, etc.)
device		acpi_panasonic

# ACPI Sony extra (LCD brightness)
device		acpi_sony

# ACPI Toshiba Extras (LCD backlight/brightness, video output, etc.)
device		acpi_toshiba

# ACPI Video Extensions (LCD backlight/brightness, video output, etc.)
device		acpi_video

# ACPI Docking Station
device		acpi_dock

# ACPI ASOC ATK0110 ASUSTeK AI Booster (voltage, temperature and fan sensors)
device		aibs

# The cpufreq(4) driver provides support for non-ACPI CPU frequency control
device		cpufreq

#
# Network interfaces:
#

# bxe:  Broadcom NetXtreme II (BCM5771X/BCM578XX) PCIe 10Gb Ethernet
#       adapters.
# ce:   Cronyx Tau-PCI/32 sync single/dual port G.703/E1 serial adaptor
#       with 32 HDLC subchannels, requires NETGRAPH
# igc:	Intel I225 2.5G Ethernet adapter
# ipw:	Intel PRO/Wireless 2100 IEEE 802.11 adapter
# iwi:	Intel PRO/Wireless 2200BG/2225BG/2915ABG IEEE 802.11 adapters
#	Requires the iwi firmware module
# iwn:	Intel Wireless WiFi Link 1000/105/135/2000/4965/5000/6000/6050 abgn
#	802.11 network adapters
#	Requires the iwn firmware module
# mthca: Mellanox HCA InfiniBand
# mlx4ib: Mellanox ConnectX HCA InfiniBand
# mlx4en: Mellanox ConnectX HCA Ethernet
# nfe:	nVidia nForce MCP on-board Ethernet Networking (BSD open source)
# sbni: Granch SBNI12-xx ISA and PCI adapters
# vmx:	VMware VMXNET3 Ethernet (BSD open source)
# wpi:	Intel 3945ABG Wireless LAN controller
#	Requires the wpi firmware module

# Order for ISA/EISA devices is important here

device          bxe             # Broadcom NetXtreme II BCM5771X/BCM578XX 10GbE
device		ce
envvar		hint.cs.0.at="isa"
envvar		hint.cs.0.port="0x300"
options 	ED_3C503
options 	ED_HPP
options 	ED_SIC
envvar		hint.ed.0.at="isa"
envvar		hint.ed.0.port="0x280"
envvar		hint.ed.0.irq="5"
envvar		hint.ed.0.maddr="0xd8000"
device		igc		# Intel I225 2.5G Ethernet
device		ipw		# Intel 2100 wireless NICs.
device		iwi		# Intel 2200BG/2225BG/2915ABG wireless NICs.
device		iwn		# Intel 4965/1000/5000/6000 wireless NICs.
# Hint for the i386-only ISA front-end of le(4).
envvar		hint.le.0.at="isa"
envvar		hint.le.0.port="0x280"
envvar		hint.le.0.irq="10"
envvar		hint.le.0.drq="0"
device  	mthca		# Mellanox HCA InfiniBand
device		mlx4		# Shared code module between IB and Ethernet
device  	mlx4ib		# Mellanox ConnectX HCA InfiniBand
device  	mlx4en		# Mellanox ConnectX HCA Ethernet
device		nfe		# nVidia nForce MCP on-board Ethernet
device		sbni
envvar		hint.sbni.0.at="isa"
envvar		hint.sbni.0.port="0x210"
envvar		hint.sbni.0.irq="0xefdead"
envvar		hint.sbni.0.flags="0"
device		vmx		# VMware VMXNET3 Ethernet
device		wpi		# Intel 3945ABG wireless NICs.

# IEEE 802.11 adapter firmware modules

# Intel PRO/Wireless 2100 firmware:
#   ipwfw:		BSS/IBSS/monitor mode firmware
#   ipwbssfw:		BSS mode firmware
#   ipwibssfw:		IBSS mode firmware
#   ipwmonitorfw:	Monitor mode firmware
# Intel PRO/Wireless 2200BG/2225BG/2915ABG firmware:
#   iwifw:		BSS/IBSS/monitor mode firmware
#   iwibssfw:		BSS mode firmware
#   iwiibssfw:		IBSS mode firmware
#   iwimonitorfw:	Monitor mode firmware
# Intel Wireless WiFi Link 4965/1000/5000/6000 series firmware:
#   iwnfw:		Single module to support all devices
#   iwn1000fw:		Specific module for the 1000 only
#   iwn105fw:		Specific module for the 105 only
#   iwn135fw:		Specific module for the 135 only
#   iwn2000fw:		Specific module for the 2000 only
#   iwn2030fw:		Specific module for the 2030 only
#   iwn4965fw:		Specific module for the 4965 only
#   iwn5000fw:		Specific module for the 5000 only
#   iwn5150fw:		Specific module for the 5150 only
#   iwn6000fw:		Specific module for the 6000 only
#   iwn6000g2afw:	Specific module for the 6000g2a only
#   iwn6000g2bfw:	Specific module for the 6000g2b only
#   iwn6050fw:		Specific module for the 6050 only
# wpifw:	Intel 3945ABG Wireless LAN Controller firmware

device		iwifw
device		iwibssfw
device		iwiibssfw
device		iwimonitorfw
device		ipwfw
device		ipwbssfw
device		ipwibssfw
device		ipwmonitorfw
device		iwnfw
device		iwn1000fw
device		iwn105fw
device		iwn135fw
device		iwn2000fw
device		iwn2030fw
device		iwn4965fw
device		iwn5000fw
device		iwn5150fw
device		iwn6000fw
device		iwn6000g2afw
device		iwn6000g2bfw
device		iwn6050fw
device		wpifw

#
# Non-Transparent Bridge (NTB) drivers
#
device		if_ntb		# Virtual NTB network interface
device		ntb_transport	# NTB packet transport driver
device		ntb		# NTB hardware interface
device		ntb_hw_amd	# AMD NTB hardware driver
device		ntb_hw_intel	# Intel NTB hardware driver
device		ntb_hw_plx	# PLX NTB hardware driver

#
# ATA raid adapters
#
device		pst

#
# Areca 11xx and 12xx series of SATA II RAID controllers.
# CAM is required.
#
device		arcmsr		# Areca SATA II RAID

#
# Adaptec FSA RAID controllers, including integrated DELL controllers,
# the Dell PERC 2/QC and the HP NetRAID-4M
device		aac
device		aacp	# SCSI Passthrough interface (optional, CAM required)

#
# Adaptec by PMC RAID controllers, Series 6/7/8 and upcoming families
device		aacraid		# Container interface, CAM required

#
# Highpoint RocketRAID 27xx.
device		hpt27xx

#
# Highpoint RocketRAID 182x.
device		hptmv

#
# Highpoint DC7280 and R750.
device		hptnr

#
# Highpoint RocketRAID.  Supports RR172x, RR222x, RR2240, RR232x, RR2340,
# RR2210, RR174x, RR2522, RR231x, RR230x.
device		hptrr

#
# Highpoint RocketRaid 3xxx series SATA RAID
device		hptiop

#
# Intel integrated Memory Controller (iMC) SMBus controller
#	Sandybridge-Xeon, Ivybridge-Xeon, Haswell-Xeon, Broadwell-Xeon
device		imcsmb

#
# IBM (now Adaptec) ServeRAID controllers
device		ips

#
# Intel C600 (Patsburg) integrated SAS controller
device		isci
options 	ISCI_LOGGING	# enable debugging in isci HAL

#
# NVM Express (NVMe) support
device         nvme    # base NVMe driver
device         nvd     # expose NVMe namespaces as disks, depends on nvme

#
# Intel Volume Management Device (VMD) support
device		vmd

#
# PMC-Sierra SAS/SATA controller
device		pmspcv
#
# SafeNet crypto driver: can be moved to the MI NOTES as soon as
# it's tested on a big-endian machine
#
device		safe		# SafeNet 1141
options 	SAFE_DEBUG	# enable debugging support: hw.safe.debug
options 	SAFE_RNDTEST	# enable rndtest support

#
# glxiic is an I2C driver for the AMD Geode LX CS5536 System Management Bus
# controller.  Requires 'device iicbus'.
#
device		glxiic		# AMD Geode LX CS5536 System Management Bus

#
# glxsb is a driver for the Security Block in AMD Geode LX processors.
# Requires 'device crypto'.
#
device		glxsb		# AMD Geode LX Security Block

#
# VirtIO support
#
# The virtio entry provides a generic bus for use by the device drivers.
# It must be combined with an interface that communicates with the host.
# Multiple such interfaces defined by the VirtIO specification. FreeBSD
# only has support for PCI. Therefore, virtio_pci must be statically
# compiled in or loaded as a module for the device drivers to function.
#
device		virtio		# Generic VirtIO bus (required)
device		virtio_pci	# VirtIO PCI Interface
device		vtnet		# VirtIO Ethernet device
device		virtio_blk	# VirtIO Block device
device		virtio_scsi	# VirtIO SCSI device
device		virtio_balloon	# VirtIO Memory Balloon device
device		virtio_random	# VirtIO Entropy device
device		virtio_console	# VirtIO Console device

# Linux KVM paravirtualization support
device 		kvm_clock	# KVM paravirtual clock driver

options 	HYPERV
device		hyperv		# HyperV drivers

#####################################################################

#
# Miscellaneous hardware:
#
# ipmi: Intelligent Platform Management Interface
# smapi: System Management Application Program Interface driver
# smbios: DMI/SMBIOS entry point
# vpd: Vital Product Data kernel interface
# pbio: Parallel (8255 PPI) basic I/O (mode 0) port (e.g. Advantech PCL-724)
# asmc: Apple System Management Controller
# si: Specialix International SI/XIO or SX intelligent serial card driver
# tpm: Trusted Platform Module

# Notes on the Specialix SI/XIO driver:
#  The host card is memory, not IO mapped.
#  The Rev 1 host cards use a 64K chunk, on a 32K boundary.
#  The Rev 2 host cards use a 32K chunk, on a 32K boundary.
#  The cards can use an IRQ of 11, 12 or 15.

# Notes on the Sony Programmable I/O controller
#  This is a temporary driver that should someday be replaced by something
#  that hooks into the ACPI layer.  The device is hooked to the PIIX4's
#  General Device 10 decoder, which means you have to fiddle with PCI
#  registers to map it in, even though it is otherwise treated here as
#  an ISA device.  At the moment, the driver polls, although the device
#  is capable of generating interrupts.  It largely undocumented.
#  The port location in the hint is where you WANT the device to be
#  mapped.  0x10a0 seems to be traditional.  At the moment the jogdial
#  is the only thing truly supported, but apparently a fair percentage
#  of the Vaio extra features are controlled by this device.

device		ipmi
device		smapi
device		smbios
device		vpd
device		pbio
envvar		hint.pbio.0.at="isa"
envvar		hint.pbio.0.port="0x360"
device		asmc
device		tpm
device		padlock_rng	# VIA Padlock RNG
device		rdrand_rng	# Intel Bull Mountain RNG
device		aesni		# AES-NI OpenCrypto module
device		ossl		# OpenSSL OpenCrypto module

#
# Laptop/Notebook options:
#
# See also:
#  apm under `Miscellaneous hardware'
# above.

device		backlight

# For older notebooks that signal a powerfail condition (external
# power supply dropped, or battery state low) by issuing an NMI:

options 	POWERFAIL_NMI	# make it beep instead of panicing

#
# I2C Bus
#
# Philips i2c bus support is provided by the `iicbus' device.
#
# Supported interfaces:
# pcf	Philips PCF8584 ISA-bus controller
#
device		pcf
envvar		hint.pcf.0.at="isa"
envvar		hint.pcf.0.port="0x320"
envvar		hint.pcf.0.irq="5"

#
# Hardware watchdog timers:
#
# ichwd: Intel ICH watchdog timer
# amdsbwd: AMD SB7xx watchdog timer
# viawd: VIA south bridge watchdog timer
# wbwd: Winbond watchdog timer
# itwd: ITE Super I/O watchdog timer
#
device		ichwd
device		amdsbwd
device		viawd
device		wbwd
device		itwd

#
# Temperature sensors:
#
# coretemp: on-die sensor on Intel Core and newer CPUs
# amdtemp: on-die sensor on AMD K8/K10/K11 CPUs
#
device		coretemp
device		amdtemp

#
# CPU control pseudo-device. Provides access to MSRs, CPUID info and
# microcode update feature.
#
device		cpuctl

#
# SuperIO driver.
#
device		superio

#
# System Management Bus (SMB)
#
options 	ENABLE_ALART		# Control alarm on Intel intpm driver

#
# Set the number of PV entries per process.  Increasing this can
# stop panics related to heavy use of shared memory.  However, that can
# (combined with large amounts of physical memory) cause panics at
# boot time due the kernel running out of VM space.
#
# If you're tweaking this, you might also want to increase the sysctls
# "vm.v_free_min", "vm.v_free_reserved", and "vm.v_free_target".
#
# The value below is the one more than the default.
#
options 	PMAP_SHPGPERPROC=201

#
# Number of initial kernel page table pages used for early bootstrap.
# This number should include enough pages to map the kernel, any
# modules or other data loaded with the kernel by the loader, and data
# structures allocated before the VM system is initialized such as the
# vm_page_t array.  Each page table page maps 4MB (2MB with PAE).
#
options 	NKPT=31

#
# HID-over-I2C support
#
device		iichid		# HID-over-I2C support
options 	IICHID_DEBUG	# Enable HID-over-I2C debug messages
options 	IICHID_SAMPLING	# Workaround missing GPIO INTR support

#####################################################################
# ABI Emulation

# Enable (32-bit) a.out binary support
options 	COMPAT_AOUT

#####################################################################
# VM OPTIONS

# KSTACK_PAGES is the number of memory pages to assign to the kernel
# stack of each thread.

options 	KSTACK_PAGES=5

# Enable detailed accounting by the PV entry allocator.

options 	PV_STATS

#####################################################################

# More undocumented options for linting.
# Note that documenting these are not considered an affront.

options 	FB_INSTALL_CDEV		# install a CDEV entry in /dev

options 	KBDIO_DEBUG=2
options 	KBD_MAXRETRY=4
options 	KBD_MAXWAIT=6
options 	KBD_RESETDELAY=201

options 	PSM_DEBUG=1

options 	TIMER_FREQ=((14318182+6)/12)

options 	VM_KMEM_SIZE
options 	VM_KMEM_SIZE_MAX
options 	VM_KMEM_SIZE_SCALE