ref: 7628681f83b663609eace87a50f8fbf68c31f40b
dir: /sys/man/8/plan9.ini/
.TH PLAN9.INI 8
.SH NAME
plan9.ini \- configuration file for PCs
.SH SYNOPSIS
.I none
.SH DESCRIPTION
When booting Plan 9 on a PC, the bootloader program
.IR 9boot (8)
first reads configuration information from a file
on the boot media.
This file,
.BR plan9.ini ,
looks like a shell script containing lines of the form
.IP
.EX
name=\f2value\fP
.EE
.LP
each of which defines a kernel or device parameter.
.PP
Blank lines and
Carriage Returns
.IB ( \er )
are ignored.
.B #
comments are ignored, but are only recognised if
.L #
appears at the start of a line.
.PP
For devices, the generic format of
.I value
is
.IP
.EX
type=TYPE [port=N] [irq=N] [mem=N] [size=N] [dma=N] [ea=N]
.EE
.LP
specifying the controller type,
the base I/O port of the interface, its interrupt
level, the physical starting address of any mapped memory,
the length in bytes of that memory, the DMA channel,
and for Ethernets an override of the physical network address.
Not all elements are relevant to all devices; the relevant values
and their defaults are defined below in the description of each device.
.PP
The file is used by the kernel to configure the hardware available.
The information it contains is also passed to the boot
process, and subsequently other programs,
as environment variables
(see
.IR boot (8)).
However, values whose names begin with an asterisk
.B *
are used by the kernel and are not converted into environment variables.
.PP
The following sections describe how variables are used.
.SS ETHERNET
.SS \fLether\fIX\fL=\fIvalue\fP
This defines an Ethernet interface.
.IR X ,
a unique monotonically increasing number beginning at 0,
identifies an Ethernet card to be probed at system boot.
Probing stops when a card is found or there is no line for
.BR etherX+1 .
After probing as directed by the
.BI ether X
lines, any remaining Ethernet cards that can be automatically
detected are added.
Almost all cards can be automatically detected.
For debugging purposes, automatic probing can
be disabled by specifying the line
.BR *noetherprobe= .
.PP
Some cards are software configurable and do not require all options.
Unspecified options default to the factory defaults.
.PP
Known
.IR TYPE s
are
.\" .TF ga620
.TF vt6102
.PD
.TP
.B igbe
The Intel 8254X Gigabit Ethernet controllers,
as found on the Intel PRO/1000 adapters for copper (not fiber).
Completely configurable.
.TP
.B igbepcie
The Intel 8256[36], 8257[12], and 82573[ev] Gigabit Ethernet
PCI-Express controllers.
Completely configurable.
.TP
.B rtl8169
The Realtek 8169 Gigabit Ethernet controller.
Completely configurable.
.TP
.B ga620
Netgear GA620 and GA620T Gigabit Ethernet cards,
and other cards using the Alteon Acenic chip such as the
Alteon Acenic fiber and copper cards,
the DEC DEGPA-SA and the SGI Acenic.
Completely configurable.
.TP
.B dp83820
National Semiconductor DP83820-based Gigabit Ethernet adapters, notably
the D-Link DGE-500T.
Completely configurable.
.TP
.B vgbe
The VIA Velocity Gigabit Ethernet controller.
Known to drive the VIA8237 (ABIT AV8), but at 100Mb/s full-duplex only.
.TP
.B m10g
The Myricom 10-Gigabit Ethernet 10G-PCIE-8A controller.
Completely configurable.
Can't boot through these due to enormous firmware loads.
.TP
.B i82598
The Intel 8259[89] 10-Gigabit Ethernet PCI-Express controllers.
Completely configurable.
.TP
.B i82557
Cards using the Intel 8255[789] Fast Ethernet PCI Bus LAN Controller such as the
Intel EtherExpress PRO/100B.
Completely configurable, no options need be given.
If you need to force the media, specify
one of the options (no value)
.BR 10BASE-T ,
.BR 10BASE-2 ,
.BR 10BASE-5 ,
.BR 100BASE-TX ,
.BR 10BASE-TFD ,
.BR 100BASE-TXFD ,
.BR 100BASE-T4 ,
.BR 100BASE-FX ,
or
.BR 100BASE-FXFD .
Completely configurable.
.TP
.B 2114x
Cards using the Digital Equipment (now Intel) 2114x PCI Fast Ethernet Adapter Controller,
for example the Netgear FA310.
Completely configurable, no options need be given.
Media can be specified the same was as for the
.BR i82557 .
Some cards using the
.B PNIC
and
.B PNIC2
near-clone chips may also work.
.TP
.B 83815
National Semiconductor DP83815-based adapters, notably
the Netgear FA311, Netgear FA312, and various SiS built-in
controllers such as the SiS900.
On the SiS controllers, the Ethernet address is not detected properly;
specify it with an
.B ea=
attribute.
Completely configurable.
.TP
.B rtl8139
The Realtek 8139 Fast Ethernet controller.
Completely configurable.
.TP
.B vt6102
The VIA VT6102 Fast Ethernet Controller (Rhine II).
.TP
.B smc91cxx
SMC 91cXX chip-based PCMCIA adapters, notably the SMC EtherEZ card.
.TP
.B elnk3
The 3COM Etherlink III series of cards including the 5x9, 59x, and 905 and 905B.
Completely configurable, no options need be given.
The media may be specified by setting
.B media=
to the value
.BR 10BaseT ,
.BR 10Base2 ,
.BR 100BaseTX ,
.BR 100BaseFX ,
.BR aui ,
and
.BR mii .
If you need to force full duplex, because for example the Ethernet switch does not negotiate correctly,
just name the word (no value)
.B fullduplex
or
.BR 100BASE-TXFD .
Similarly, to force 100Mbit operation, specify
.BR force100 .
Port 0x110 is used for the little ISA configuration dance.
.TP
.B 3c589
The 3COM 3C589 series PCMCIA cards, including the
3C562 and the 589E.
There is no support for the modem on the 3C562.
Completely configurable, no options need be given.
Defaults are
.EX
port=0x240 irq=10
.EE
The media may be specified as
.B media=10BaseT
or
.BR media=10Base2 .
.TP
.B ec2t
The Linksys Combo PCMCIA EthernetCard (EC2T),
EtherFast 10/100 PCMCIA cards (PCMPC100) and integrated controllers (PCM100),
the Netgear FA410TX 10/100 PCMCIA card
and the Accton EtherPair-PCMCIA (EN2216).
Completely configurable, no options need be given.
Defaults are
.EX
port=0x300 irq=9
.EE
These cards are NE2000 clones.
Other NE2000 compatible PCMCIA cards may be tried
with the option
.EX
id=string
.EE
where
.B string
is a unique identifier string contained in the attribute
memory of the card (see
.IR pcmcia (8));
unlike most options in
.BR plan9.ini ,
this string is case-sensitive.
The option
.B dummyrr=[01]
can be used to turn off (0) or on (1) a dummy remote read in the driver
in such cases,
depending on how NE2000 compatible they are.
.TP
.B ne2000
Not software configurable iff ISA;
PCI clones or supersets are software configurable;
includes the Realtek 8029 clone used by Parallels.
16-bit card.
Defaults are
.EX
port=0x300 irq=2 mem=0x04000 size=0x4000
.EE
The option (no value)
.B nodummyrr
is needed on some (near) clones to turn off a dummy remote read in the driver.
.TP
.B amd79c970
The AMD PCnet PCI Ethernet Adapter (AM79C970).
(This is the Ethernet adapter used by VMware.)
Completely configurable, no options need be given.
.TP
.B wd8003
Includes WD8013 and SMC Elite and Elite Ultra cards. There are varying degrees
of software configurability. Cards may be in either 8-bit or 16-bit slots.
Defaults are
.EX
port=0x280 irq=3 mem=0xD0000 size=0x2000
.EE
BUG: On many machines only the 16 bit card works.
.TP
.B bcm
Broadcom BCM57xx Gigabit Ethernet controllers.
Completely configurable, no options need be given.
.TP
.B yuk
Marvell 88e8057 Yukon2 Gigabit Ethernet controller.
Completely configurable, no options need be given.
.TP
.B virtio
Virtual Ethernet interface provided by QEMU/KVM and VirtualBox.
No options need be given. The MAC address can be changed with the
.B ea=
option.
.TP
.B sink
A
.B /dev/null
for Ethernet packets \(em the interface discards sent
packets and never receives any.
This is used to provide a test bed for
some experimental Ethernet bridging software.
.TP
.B wavelan
Lucent Wavelan (Orinoco) IEEE 802.11b
and compatible PCMCIA cards.
Compatible cards include the Dell TrueMobile 1150
and the Linksys Instant Wireless Network PC Card.
Port and IRQ defaults are 0x180 and 3 respectively.
.IP
These cards take a number of unique options to aid in
identifying the card correctly on the 802.11b network.
The network may be
.I "ad hoc"
or
.I managed
(i.e. use an access point):
.EX
mode=[adhoc, managed]
.EE
and defaults to
.IR managed .
The 802.11b network to attach to
.RI ( managed
mode)
or identify as
.RI ( "ad hoc"
mode),
is specified by
.EX
essid=string
.EE
and defaults to a null string.
The card station name is given by
.EX
station=string
.EE
and defaults to
.IR "Plan 9 STA" .
The channel to use is given by
.EX
channel=number
.EE
where
.I number
lies in the range 1 to 16 inclusive;
the channel is normally negotiated automatically.
.IP
If the card is capable of encryption,
the following options may be used:
.EX
crypt=[off, on]
.EE
and defaults to
.IR on .
.EX
key\fIN\fP=string
.EE
sets the encryption key
.I N
(where
.I N
is in the range 1 to 4 inclusive) to
.IR string ;
this will also set the transmit key to
.I N
(see below).
There are two formats for
.I string
which depend on the length of the string.
If it is exactly 5 or 13 characters long it is assumed
to be an alphanumeric key; if it is exactly 10 or 26 characters
long the key is assumed to be in hex format (without a leading
.IR 0x ).
The lengths are checked,
as is the format of a hex key.
.EX
txkey=number
.EE
sets the transmit key to use to be
.I number
in the range 1 to 4 inclusive.
If it is desired to exclude or include unencrypted packets
.EX
clear=[off, on]
.EE
configures reception and defaults to inclusion.
.IP
The defaults are intended to match the common case of
a managed network with encryption and a typical entry would
only require, for example
.EX
essid=left-armpit key1=afish key2=calledraawaru
.EE
if the port and IRQ defaults are used.
These options may be set after boot by writing to the device's
.I ctl
file using a space as the separator between option and value, e.g.
.EX
echo 'key2 1d8f65c9a52d83c8e4b43f94af' >/net/ether0/0/ctl
.EE
.IP
Card-specific power management may be enabled/disabled by
.EX
pm=[on, off]
.EE
.TP
.B wavelanpci
PCI Ethernet adapters that use the same Wavelan
programming interface.
Currently the only tested cards are those based on the
Intersil Prism 2.5 chipset.
.
.TP
.B iwl
Intel Wireless WiFi Link mini PCI-Express adapters require
firmware from
.B http://firmware.openbsd.org/firmware/*/iwn-firmware*.tgz
to be present on attach in
.B /lib/firmware
or
.B /boot.
To limit the selected APs the options
.B essid=
and
.B bssid=
may be set at boot or in the ether interface clone file
using a space as the separator between option and value, e.g.
.EX
echo essid left-armpit >/net/ether1/clone
.EE
Scan results appear in the
.B ifstats
file and can be read out like:
.EX
cat /net/ether1/ifstats
.EE
Ad-hoc mode or WEP encryption is currently not supported.
.TP
.B rt2860
Ralink Technology PCI/PCI-Express wireless adapters require
firmware from
.B http://firmware.openbsd.org/firmware/*/ral-firmware*.tgz
to be present on attach in
.B /lib/firmware
or
.B /boot.
See iwl section above for configuration details.
.TP
.B wpi
Intel PRO Wireless 3945abg PCI/PCI-Express wireless adapters require
firmware from
.B http://firmware.openbsd.org/firmware/*/wpi-firmware*.tgz
to be present on attach in
.B /lib/firmware
or
.B /boot.
See iwl section above for configuration details.
.SS \fLwpapsk\fI=password\fP
WPA/WPA2 encryption
is detected automatically and a prompt for the
.I password
will appear when using the WIFI interface for netbooting.
To avoid the prompt, the
.I password
can be specified with the boot parameter above.
.SS \fLwpaopts=\fivalue\fP
Pass
.I value
as additional options to
.IR wpa (8).
.SS \fLnora6=
Disable automatic IPv6 configuration from incoming router advertisements.
.SS DISKS, TAPES
PCI based controllers such as (S)ATA and NVMe are autodetected.
.SS \fL*nodma=\fP
disables dma on ata devices.
.SS \fL*sd\fIXX\fLdma=on\fP
explicitly enables dma on a specific ata device.
.SS \fLscsi\fIX\fL=value\fP
This defines a SCSI interface which cannot be automatically detected
by the kernel.
.PP
Known
.IR TYPE s
are
.TP
.B aha1542
Adaptec 154x series of controllers (and clones).
Almost completely configurable, only the
.EX
port=0x300
.EE
option need be given.
.PP
NCR/Symbios/LSI-Logic 53c8xx-based adapters
and Mylex MultiMaster (Buslogic BT-*) adapters are
automatically detected and need no entries.
.PP
By default, the NCR 53c8xx driver searches for up to 32 controllers.
This can be changed by setting the variable
.BR *maxsd53c8xx .
.PP
By default the Mylex driver resets SCSI cards by using
both the hard reset and SCSI bus reset flags in the driver interface.
If a variable
.BR *noscsireset
is defined, the SCSI bus reset flag is omitted.
.SS \fLaoeif=\fP\fIlist\fP
This specifies a space-separated
.I list
of Ethernet interfaces to be bound at boot to the ATA-over-Ethernet driver,
.IR aoe (3).
For example,
.LR "aoeif=ether0 ether1" .
Only interfaces on this list will initially be accessible via AoE.
.SS \fLaoedev=e!#æ/aoe/\fIshelf\fL.\fIslot\fR
This specifies an ATA-over-Ethernet device accessible via the interfaces
named in
.IR aoeif
on AoE
.I shelf
and
.I slot
to use as a root device for bootstrapping.
.SS \fLramdisk\fIX\fL=\fIsize\fP
.SS \fLramdisk\fIX\fL=\fIsize sectorsize\fP
.SS \fLramdisk\fIX\fL=\fIaddress size sectorsize\fP
This reserves physical memory as a ramdisk that will appear as
.IR sd (3)
device \fLsdZ\fIX\fR.
When the
.I address
argument is omited or zero, then the ramdisk will be allocated
from the top of physical memory.
.SS AUDIO
.SS \fLaudio\fIX\fL=\fIvalue\fP
This defines a sound interface. PCI-based audio devices such as
Intel HD audio or AC97 are autodetected and do not require any settings.
.PP
Known types are
.TF ess1688
.PD
.TP
.B hda
Intel HD audio.
.TP
.B ac97
AC97 based card.
.TP
.B sb16
Sound Blaster 16.
.TP
.B ess1688
A Sound Blaster clone.
.PP
The DMA channel may be any of 5, 6, or 7.
The defaults are
.IP
.EX
port=0x220 irq=7 dma=5
.EE
.SS UARTS
Plan 9 automatically configures COM1 and COM2, if found,
as
.B eia0
(port 0x3F8, IRQ4)
and
.B eia1
(port 0x2F8, IRQ3)
respectively.
These devices can be disabled by adding a line:
.IP
.EX
eia\fIX\fP=disabled
.EE
.LP
This is typically done in order to reuse the IRQ for
another device.
.P
.PP
Additional i8250 (ISA) uarts (uart2 to uart5) can be
configured using:
.IP
.EX
uart\fIX\fP=type=isa port=\fIport\fP irq=\fIirq
.EE
.PP
Perle PCI-Fast4, PCI-Fast8, and PCI-Fast16 controllers
are automatically detected and need no configuration lines.
.PP
The line
.B serial=type=com
can be used to specify settings for a PCMCIA modem.
.SS \fLconsole=\fIvalue params\fP
This is used by the kernel and
.IR 9boot (8)
to specify the console device.
A number
.B 0
or
.B 1
specifies
.I COM1
or
.I COM2
respectively.
A serial console is initially configured with the
.IR uart (3)
configuration string
.B b9600
.B l8
.B pn
.BR s1 ,
specifying 9600 baud,
8 bit bytes, no parity, and one stop bit.
If
.I params
is given, it will be used by the kernel to further
configure the uart.
Due to BIOS limitations,
.IR 9boot (8)
ignores
.I params
and always assumes the default configuration.
Notice that there is no
.B =
sign in the
.I params
syntax.
For example,
.IP
.EX
console=0 b19200 po
.EE
.LP
would use COM1 at 19,200 baud
with odd parity.
.LP
The value
.B net
specifies ``netconsole'' which sends console messages as UDP packets over the network.
It bypasses the IP stack and writes Ethernet packets directly to the NIC.
In this case
.I params
is mandatory and takes the form
.IP
\fIsrcip\fR [ \fB!\fIsrcport \fR] [ \fB/\fIdevno \fR] \fB, \fIdstip\fR [ \fB!\fIdstport \fR] [ \fB/\fIdstmac \fR]
.LP
\fISrcip\fR, \fIsrcport\fR (default 6665), \fIdstip\fR and \fIdstport\fR (default 6666) specify the source IP address, source port, destination IP address and destination port, respectively.
\fIDevno\fR (default 0) specifies which NIC to use, a value of \fIn\fR corresponds to NIC at \fL#l\fIn\fR (see
.IR ether (3)).
\fIDstmac\fR specifies the destination MAC address; broadcast packets are sent if it is unspecified.
Note that it is possible, but not recommended, to send packets to a host outside the local network by specifying the MAC address of the gateway as \fIdstmac\fR.
Example lines are
.IP
.EX
console=net 192.168.0.4,192.168.0.8
console=net 192.168.2.10!1337/1,192.168.2.3!1337/0ea7deadbeef
.EE
.LP
.SS KEYBOARD
USB keyboards are automatically detected.
.SS \fL*nokbd=\fP
This inhibits the kernel and
.IR 9boot (8)
from reading from the PS2 keyboard.
.SS \fLkbmap=\fIvalue\fP
This specifies the keyboard map to use.
.I Value
can be a map file found in
.B /sys/lib/kbmap
on the ramdisk.
.PP
For example:
.TP
.B kbmap=colemak
.SS MOUSE
USB mice are automatically detected.
.SS \fLmouseport=\fIvalue\fP
This specifies where the mouse is attached.
.TP
.B ps2
the PS2 mouse/keyboard port. The BIOS setup procedure
should be used to configure the machine appropriately.
.TP
.B ps2intellimouse
an Intellimouse on the PS2 port.
.TP
.B 0
for COM1
.TP
.B 1
for COM2
.SS "PC CARD"
.SS \fLpccard0=disabled\fP
Disable probing for and automatic configuration of PC card controllers.
.SS \fLpcmcia\fIX\fL=type=XXX irq=\fIvalue\fP
If the default IRQ for the
PCMCIA
is correct, this entry can be omitted. The value of
.B type
is ignored.
.SS \fLpcmcia0=disabled\fP
Disable probing for and automatic configuration of PCMCIA controllers.
.SS BOOTING
.SS \fLbootfile=\fIvalue\fP
This is used to direct the actions of
.IR 9boot (8)
by naming the file from which to load the kernel in
the current BIOS boot device.
.SS \fLbootargs=\fIvalue\fP
The
.I value
of this variable is passed to
.IR boot (8)
by the kernel as the name of the root file system to
automatically mount and boot into.
It is typically used to specify additional arguments to
pass to
.IR cwfs (4)
or
.IR ipconfig (8).
For example, if the system is to run from a local
.IR cwfs (4)
partition, the definition might read
.BR bootargs=local!/dev/sdC0/fscache .
See
.IR boot (8)
for more.
.SS \fLnobootprompt=\fIvalue\fP
Suppress the
.L bootargs
prompt and use
.I value
as the answer instead.
.SS \fLbootloop=\fIvalue\fP
Always use
.I value
as the answer to the
.L bootargs
prompt, retrying if unsuccessful.
.SS \fLrootdir=\fB/root/\fIdir\fP
.SS \fLrootspec=\fIspec\fP
Changes the mount arguments for the root file server
that was specified by
.I bootargs
above.
By changing
.I dir
in
.BR $rootdir ,
a different sub-directory on the root file server
can be used as the system root. see
.IR boot (8)
for details.
.SS \fLuser=\fIvalue\fP
Suppress the
.L "user"
prompt and use
.I value
as the answer instead.
.SS \fLservice=\fIvalue\fP
Changes the systems default role. Possible
settings for
.I value
are
.B cpu
and
.B terminal.
.SS \fLsysname=\fIvalue\fP
Override the systems name and skip the
usual lookup done by
.B ndb/cs (see
.IR ndb (8)).
.SS \fLdebugfactotum=\fP
Causes
.IR boot (8)
to start
.I factotum
with the
.B -p
option, so that it can be debugged.
.SS \fLcfs=\fIvalue\fP
This gives the name of the file holding the disk partition
for the cache file system,
.IR cfs (4).
Extending the
.B bootargs
example, one would write
.BR cfs=#S/sdC0/cache .
.SS \fLbootdisk=\fIvalue\fP
This deprecated variable was used to specify the disk used by
the cache file system and other disk-resident services.
It is superseded by
.B bootargs
and
.BR cfs .
.SS \fLfs=\fIaddress\fP
.SS \fLauth=\fIaddress\fP
.SS \fLsecstore=\fIaddress\fP
These specify the network address (IP or domain name)
of the file, authentication and secstore server
to use when mounting a network-provided root file system.
When not specified, then these settings are determined via DHCP.
When
.B secstore
is not specified, then the authentication server is used.
.SS MEMORY
.SS \fL*e820=\fItype \fB0x\fIstart \fB0x\fIend ...\fP
This variable is automatically generated by the boot loader (see
.IR 9boot (8))
by doing a BIOS E820 memory scan while still in realmode and
passed to the kernel. The format is an unordered list of
decimal region
.I type
and hexadecimal 64-bit
.I start
and
.I end
addresses of the area.
.SS \fLumbexclude=\fIvalue\fP
Specifies a list of ranges of UMB to exclude from use by drivers.
Ranges are inclusive on both ends and separated by commas.
For example:
.EX
umbexclude=0xD1800-0xD3FFF
.EE
.SS \fL*maxmem=\fIvalue\fP
This defines the maximum physical address that the system will scan when sizing memory.
By default the PC operating system will scan up to 3.75 gigabytes
(0xF0000000, the base of kernel virtual address space), but setting
.B *maxmem
will limit the scan.
.B *maxmem
must be less than 3.75 gigabytes.
This variable is not consulted if using the E820 memory map.
.SS \fL*kernelpercent=\fIvalue\fP
This defines what percentage of available memory is reserved for the kernel allocation pool.
The remainder is left for user processes. The default
.I value
is
.B 30
on CPU servers,
.B 60
on terminals with less than 16MB of memory,
and
.B 40
on terminals with memories of 16MB or more.
Terminals use more kernel memory because
.IR draw (3)
maintains its graphic images in kernel memory.
This deprecated option is rarely necessary in newer kernels.
.SS \fL*imagemaxmb=\fIvalue\fP
This limits the maximum amount of memory (in megabytes) the graphics
image memory pool can grow. The default is unlimited for terminals
and cpu servers.
.SS PROCESSOR
.SS \fL*noavx=\fP
Disables AVX and AVX2 on AMD64 CPUs.
.SS \fL*nomce=\fP
If machine check exceptions are supported by the processor,
then they are enabled by default.
Setting
.B *nomce
causes them to be disabled even when available.
.SS \fL*nomp=\fP
A multiprocessor machine will enable all processors by default.
Setting
.B *nomp
restricts the kernel to starting only one processor and using the
traditional interrupt controller.
.SS \fL*ncpu=\fIvalue\fP
Setting
.B *ncpu
restricts the kernel to starting at most
.I value
processors.
.SS \fL*apicdebug=\fP
Prints a summary of the multiprocessor APIC interrupt configuration.
.SS \fL*nomsi=\fP
Disables message signaled interrupts for PCI devices.
This option has no effect when
.B *nomp
is set.
.SS \fL*nomtrr=\fP
Disables memory type range register (MTRR) support when set. (debug)
.SS \fL*notsc=\fP
Disables the use of the per processor timestamp counter registers
as high resolution clock.
.SS \fL*nohpet=\fP
Disables the HPET timer to be used as the high resolution clock.
.SS \fL*pcimaxbno=value\fP
This puts a limit on the maximum bus number probed
on a PCI bus (default 7).
For example, a
.I value
of 1 should suffice on a 'standard' motherboard with an AGP slot.
This, and
.B *pcimaxdno
below are rarely used and only on troublesome or suspect hardware.
.SS \fL*pcimaxdno=\fIvalue\fP
This puts a limit on the maximum device number probed
on a PCI bus (default 31).
.SS \fL*nopcirouting=\fP
Disable pci routing during boot. May solve interrupt routing
problems on certain machines.
.SS \fL*pcihinv=\fP
Prints a summary of the detected PCI busses and devices.
.\" .SS \fL*nobios=\fP
.\" what does this do? something with pci
.SS \fL*debug=\fP
Prevents cpu servers from rebooting on kernel panic, to enable
inspection of panic messages.
.SS \fL*nodumpstack=\fP
Disable printing a stack dump on panic.
Useful if there is only a limited cga screen available,
otherwise the textual information about the panic may scroll off.
.SS \fL*acpi=\fIvalue\fP
This option controls the search for ACPI tables by the kernel.
The
.I value
is the hexadecimal physical address of the RSD structure
and is passed by the EFI bootloer
.IR 9boot (8)
automatically.
The special
.I value
of 1 or empty make the kernel search for the structure
in BIOS memory area (This is the default).
The
special
.I value
of 0 will disable ACPI support (for interrupt routing)
in the kernel,
but still make table data available in
.B #P/acpitbls
file of the
.IR arch (3)
device.
.SS \fLapm0=\fP
This enables the ``advanced power management'' interface
as described in
.IR apm (3)
and
.IR apm (8).
The main feature of the interface is the ability to watch
battery life (see
.IR stats (8)).
It is not on by default because it causes problems on some laptops.
.SS \fLioexclude=\fIvalue\fP
Specifies a list of ranges of I/O ports to exclude from use by drivers.
Ranges are inclusive on both ends and separated by commas.
For example:
.EX
ioexclude=0x330-0x337,0x430-0x43F
.EE
.SS USB
.SS \fL*nousbprobe=\fP
Disable USB host controller detection.
.SS \fL*nousbohci=\fP
.SS \fL*nousbuhci=\fP
.SS \fL*nousbehci=\fP
.SS \fL*nousbxhci=\fP
Disable specific USB host controller types.
.SS \fLnousbrc=\fP
Disable
.IR nusbrc (8)
startup at boot time.
.SS \fLnousbhname=\fP
When defined,
.IR nusbrc (8)
will use the dynamically assigned usb device address to name
usb devices instead of the device unique name.
.SS VIDEO
.SS \fL*nocga=\fP
This inhibits the kernel and
.IR 9boot (8)
from using the CGA text console.
.SS \fLmonitor=\fIvalue\fP
.SS \fLvgasize=\fIvalue\fP
These are used not by the kernel but by
.B screenrc
which is called from
.I termrc
(see
.IR cpurc (8))
when starting
.IR vga (8).
If
.I value
is set to
.B ask
then the user is prompted for a choice on boot.
.SS \fL*bootscreen=\fIvalue\fP
This is used by the kernel to attach a pre-initialized
linear framebuffer that was setup by the bootloader
or firmware.
The
.I value
has four space separated fields: the resolution and bitdepth
of the screen, the color channel descriptor, the physical
address of the framebuffer and a optional aperture size.
.EX
*bootscreen=800x600x32 x8r8g8b8 0x80000000 0x001d4c00
.EE
.SS \fL*dpms=\fIvalue\fP
This is used to specify the screen blanking behavior of the MGA4xx
video driver.
Values are
.BR standby ,
.BR suspend ,
and
.BR off .
The first two specify differing levels of power saving;
the third turns the monitor off completely.
.SS \fL*tiltscreen=\fIvalue\fP
This is used to orient the screen on startup.
Values are
.BR left ,
.BR right ,
.BR inverted ,
and
.BR none .
If no value is given, the default is none.
.SS NVRAM
.SS \fLnvram=\fIfile\fP
.SS \fLnvrlen=\fIlength\fP
.SS \fLnvroff=\fIoffset\fP
This is used to specify an nvram device and optionally the length of the ram
and read/write offset to use.
These values are consulted by
.I readnvram
(see
.IR authsrv (2)).
The most common use of the nvram is to hold a
.IR secstore (1)
password for use by
.IR factotum (4).
.SS \fLnvr=\fIvalue\fP
This is used by the WORM file server kernel to locate a file holding information
to configure the file system.
The file cannot live on a SCSI disk.
The default is
.B fd!0!plan9.nvr
(sic),
unless
.B bootfile
is set, in which case it is
.B plan9.nvr
on the same disk as
.BR bootfile .
The syntax is either
.BI fd! unit ! name
or
.BI hd! unit ! name
where
.I unit
is the numeric unit id.
This variant syntax is a vestige of the file server kernel's origins.
.SH EXAMPLES
.PP
A representative
.BR plan9.ini :
.IP
.EX
% cat /n/9fat:/plan9.ini
ether0=type=3C509
mouseport=ps2
modemport=1
serial0=type=generic port=0x3E8 irq=5
monitor=445x
vgasize=1600x1200x8
bootfile=/386/9pc
%
.EE
.SH "SEE ALSO"
.IR 9boot (8),
.IR booting (8),
.IR boot (8)