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                                  Command Line Options for Linux/m68k

                                  ===================================

Last Update: 2 May 1999

Linux/m68k version: 2.2.6

Author: Roman.Hodek@informatik.uni-erlangen.de (Roman Hodek)

Update: jds@kom.auc.dk (Jes Sorensen) and faq@linux-m68k.org (Chris Lawrence)

0) Introduction

===============

  Often I've been asked which command line options the Linux/m68k

kernel understands, or how the exact syntax for the ... option is, or

... about the option ... . I hope, this document supplies all the

answers...

  Note that some options might be outdated, their descriptions being

incomplete or missing. Please update the information and send in the

patches.

1) Overview of the Kernel's Option Processing

=============================================

The kernel knows three kinds of options on its command line:

  1) kernel options

  2) environment settings

  3) arguments for init

To which of these classes an argument belongs is determined as

follows: If the option is known to the kernel itself, i.e. if the name

(the part before the '=') or, in some cases, the whole argument string

is known to the kernel, it belongs to class 1. Otherwise, if the

argument contains an '=', it is of class 2, and the definition is put

into init's environment. All other arguments are passed to init as

command line options.

  This document describes the valid kernel options for Linux/m68k in

the version mentioned at the start of this file. Later revisions may

add new such options, and some may be missing in older versions.

  In general, the value (the part after the '=') of an option is a

list of values separated by commas. The interpretation of these values

is up to the driver that "owns" the option. This association of

options with drivers is also the reason that some are further

subdivided.

2) General Kernel Options

=========================

2.1) root=

----------

Syntax: root=/dev/

    or: root=

This tells the kernel which device it should mount as the root

filesystem. The device must be a block device with a valid filesystem

on it.

  The first syntax gives the device by name. These names are converted

into a major/minor number internally in the kernel in an unusual way.

Normally, this "conversion" is done by the device files in /dev, but

this isn't possible here, because the root filesystem (with /dev)

isn't mounted yet... So the kernel parses the name itself, with some

hardcoded name to number mappings. The name must always be a

combination of two or three letters, followed by a decimal number.

Valid names are:

  /dev/ram: -> 0x0100 (initial ramdisk)

  /dev/hda: -> 0x0300 (first IDE disk)

  /dev/hdb: -> 0x0340 (second IDE disk)

  /dev/sda: -> 0x0800 (first SCSI disk)

  /dev/sdb: -> 0x0810 (second SCSI disk)

  /dev/sdc: -> 0x0820 (third SCSI disk)

  /dev/sdd: -> 0x0830 (forth SCSI disk)

  /dev/sde: -> 0x0840 (fifth SCSI disk)

  /dev/fd : -> 0x0200 (floppy disk)

  /dev/xda: -> 0x0c00 (first XT disk, unused in Linux/m68k)

  /dev/xdb: -> 0x0c40 (second XT disk, unused in Linux/m68k)

  /dev/ada: -> 0x1c00 (first ACSI device)

  /dev/adb: -> 0x1c10 (second ACSI device)

  /dev/adc: -> 0x1c20 (third ACSI device)

  /dev/add: -> 0x1c30 (forth ACSI device)

The last four names are available only if the kernel has been compiled

with Atari and ACSI support.

  The name must be followed by a decimal number, that stands for the

partition number. Internally, the value of the number is just

added to the device number mentioned in the table above. The

exceptions are /dev/ram and /dev/fd, where /dev/ram refers to an

initial ramdisk loaded by your bootstrap program (please consult the

instructions for your bootstrap program to find out how to load an

initial ramdisk). As of kernel version 2.0.18 you must specify

/dev/ram as the root device if you want to boot from an initial

ramdisk. For the floppy devices, /dev/fd, the number stands for the

floppy drive number (there are no partitions on floppy disks). I.e.,

/dev/fd0 stands for the first drive, /dev/fd1 for the second, and so

on. Since the number is just added, you can also force the disk format

by adding a number greater than 3. If you look into your /dev

directory, use can see the /dev/fd0D720 has major 2 and minor 16. You

can specify this device for the root FS by writing "root=/dev/fd16" on

the kernel command line.

[Strange and maybe uninteresting stuff ON]

  This unusual translation of device names has some strange

consequences: If, for example, you have a symbolic link from /dev/fd

to /dev/fd0D720 as an abbreviation for floppy driver #0 in DD format,

you cannot use this name for specifying the root device, because the

kernel cannot see this symlink before mounting the root FS and it

isn't in the table above. If you use it, the root device will not be

set at all, without an error message. Another example: You cannot use a

partition on e.g. the sixth SCSI disk as the root filesystem, if you

want to specify it by name. This is, because only the devices up to

/dev/sde are in the table above, but not /dev/sdf. Although, you can

use the sixth SCSI disk for the root FS, but you have to specify the

device by number... (see below). Or, even more strange, you can use the

fact that there is no range checking of the partition number, and your

knowledge that each disk uses 16 minors, and write "root=/dev/sde17"

(for /dev/sdf1).

[Strange and maybe uninteresting stuff OFF]

  If the device containing your root partition isn't in the table

above, you can also specify it by major and minor numbers. These are

written in hex, with no prefix and no separator between. E.g., if you

have a CD with contents appropriate as a root filesystem in the first

SCSI CD-ROM drive, you boot from it by "root=0b00". Here, hex "0b" =

decimal 11 is the major of SCSI CD-ROMs, and the minor 0 stands for

the first of these. You can find out all valid major numbers by

looking into include/linux/major.h.

2.2) ro, rw

-----------

Syntax: ro

    or: rw

These two options tell the kernel whether it should mount the root

filesystem read-only or read-write. The default is read-only, except

for ramdisks, which default to read-write.

2.3) debug

----------

Syntax: debug

This raises the kernel log level to 10 (the default is 7). This is the

same level as set by the "dmesg" command, just that the maximum level

selectable by dmesg is 8.

2.4) debug=

-----------

Syntax: debug=

This option causes certain kernel messages be printed to the selected

debugging device. This can aid debugging the kernel, since the

messages can be captured and analyzed on some other machine. Which

devices are possible depends on the machine type. There are no checks

for the validity of the device name. If the device isn't implemented,

nothing happens.

  Messages logged this way are in general stack dumps after kernel

memory faults or bad kernel traps, and kernel panics. To be exact: all

messages of level 0 (panic messages) and all messages printed while

the log level is 8 or more (their level doesn't matter). Before stack

dumps, the kernel sets the log level to 10 automatically. A level of

at least 8 can also be set by the "debug" command line option (see

2.3) and at run time with "dmesg -n 8".

Devices possible for Amiga:

 - "ser": built-in serial port; parameters: 9600bps, 8N1

 - "mem": Save the messages to a reserved area in chip mem. After

          rebooting, they can be read under AmigaOS with the tool

          'dmesg'.

Devices possible for Atari:

 - "ser1": ST-MFP serial port ("Modem1"); parameters: 9600bps, 8N1

 - "ser2": SCC channel B serial port ("Modem2"); parameters: 9600bps, 8N1

 - "ser" : default serial port

           This is "ser2" for a Falcon, and "ser1" for any other machine

 - "midi": The MIDI port; parameters: 31250bps, 8N1

 - "par" : parallel port

           The printing routine for this implements a timeout for the

           case there's no printer connected (else the kernel would

           lock up). The timeout is not exact, but usually a few

           seconds.

2.6) ramdisk=

-------------

Syntax: ramdisk=

  This option instructs the kernel to set up a ramdisk of the given

size in KBytes. Do not use this option if the ramdisk contents are

passed by bootstrap! In this case, the size is selected automatically

and should not be overwritten.

  The only application is for root filesystems on floppy disks, that

should be loaded into memory. To do that, select the corresponding

size of the disk as ramdisk size, and set the root device to the disk

drive (with "root=").

2.7) swap=

2.8) buff=

-----------

  I can't find any sign of these options in 2.2.6.

3) General Device Options (Amiga and Atari)

===========================================

3.1) ether=

-----------

Syntax: ether=[[,[,[,]]]],

   is the name of a net driver, as specified in

drivers/net/Space.c in the Linux source. Most prominent are eth0, ...

eth3, sl0, ... sl3, ppp0, ..., ppp3, dummy, and lo.

  The non-ethernet drivers (sl, ppp, dummy, lo) obviously ignore the

settings by this options. Also, the existing ethernet drivers for

Linux/m68k (ariadne, a2065, hydra) don't use them because Zorro boards

are really Plug-'n-Play, so the "ether=" option is useless altogether

for Linux/m68k.

3.2) hd=

--------

Syntax: hd=,,

  This option sets the disk geometry of an IDE disk. The first hd=

option is for the first IDE disk, the second for the second one.

(I.e., you can give this option twice.) In most cases, you won't have

to use this option, since the kernel can obtain the geometry data

itself. It exists just for the case that this fails for one of your

disks.

3.3) max_scsi_luns=

-------------------

Syntax: max_scsi_luns=

  Sets the maximum number of LUNs (logical units) of SCSI devices to

be scanned. Valid values for  are between 1 and 8. Default is 8 if

"Probe all LUNs on each SCSI device" was selected during the kernel

configuration, else 1.

3.4) st=

--------

Syntax: st=,[,[]]

  Sets several parameters of the SCSI tape driver.  is

the number of 512-byte buffers reserved for tape operations for each

device.  sets the number of blocks which must be filled

to start an actual write operation to the tape. Maximum value is the

total number of buffers.  limits the total number of

buffers allocated for all tape devices.

3.5) dmasound=

--------------

Syntax: dmasound=[,[,]]

  This option controls some configurations of the Linux/m68k DMA sound

driver (Amiga and Atari):  is the number of buffers you want

to use (minimum 4, default 4),  is the size of each

buffer in kilobytes (minimum 4, default 32) and  says

how much percent of error will be tolerated when setting a frequency

(maximum 10, default 0). For example with 3% you can play 8000Hz

AU-Files on the Falcon with its hardware frequency of 8195Hz and thus

don't need to expand the sound.

4) Options for Atari Only

=========================

4.1) video=

-----------

Syntax: video=:

The  parameter specifies the name of the frame buffer,

eg. most atari users will want to specify `atafb' here. The

 is a comma-separated list of the sub-options listed

below.

NB: Please notice that this option was renamed from `atavideo' to

    `video' during the development of the 1.3.x kernels, thus you

    might need to update your boot-scripts if upgrading to 2.x from

    an 1.2.x kernel.

NBB: The behavior of video= was changed in 2.1.57 so the recommended

option is to specify the name of the frame buffer.

4.1.1) Video Mode

-----------------

This sub-option may be any of the predefined video modes, as listed

in atari/atafb.c in the Linux/m68k source tree. The kernel will

activate the given video mode at boot time and make it the default

mode, if the hardware allows. Currently defined names are:

 - stlow           : 320x200x4

 - stmid, default5 : 640x200x2

 - sthigh, default4: 640x400x1

 - ttlow           : 320x480x8, TT only

 - ttmid, default1 : 640x480x4, TT only

 - tthigh, default2: 1280x960x1, TT only

 - vga2            : 640x480x1, Falcon only

 - vga4            : 640x480x2, Falcon only

 - vga16, default3 : 640x480x4, Falcon only

 - vga256          : 640x480x8, Falcon only

 - falh2           : 896x608x1, Falcon only

 - falh16          : 896x608x4, Falcon only

  If no video mode is given on the command line, the kernel tries the

modes names "default" in turn, until one is possible with the

hardware in use.

  A video mode setting doesn't make sense, if the external driver is

activated by a "external:" sub-option.

4.1.2) inverse

--------------

Invert the display. This affects both, text (consoles) and graphics

(X) display. Usually, the background is chosen to be black. With this

option, you can make the background white.

4.1.3) font

-----------

Syntax: font:

Specify the font to use in text modes. Currently you can choose only

between `VGA8x8', `VGA8x16' and `PEARL8x8'. `VGA8x8' is default, if the

vertical size of the display is less than 400 pixel rows. Otherwise, the

`VGA8x16' font is the default.

4.1.4) hwscroll_

----------------

Syntax: hwscroll_

The number of additional lines of video memory to reserve for

speeding up the scrolling ("hardware scrolling"). Hardware scrolling

is possible only if the kernel can set the video base address in steps

fine enough. This is true for STE, MegaSTE, TT, and Falcon. It is not

possible with plain STs and graphics cards (The former because the

base address must be on a 256 byte boundary there, the latter because

the kernel doesn't know how to set the base address at all.)

  By default,  is set to the number of visible text lines on the

display. Thus, the amount of video memory is doubled, compared to no

hardware scrolling. You can turn off the hardware scrolling altogether

by setting  to 0.

4.1.5) internal:

----------------

Syntax: internal:;[;;;]

This option specifies the capabilities of some extended internal video

hardware, like e.g. OverScan.  and  give the (extended)

dimensions of the screen.

  If your OverScan needs a black border, you have to write the last

three arguments of the "internal:".  is the maximum line

length the hardware allows,  the maximum number of lines.

 is the offset of the visible part of the screen memory to its

physical start, in bytes.

  Often, extended interval video hardware has to be activated somehow.

For this, see the "sw_*" options below.

4.1.6) external:

----------------

Syntax:

  external:;;;;[;[;\

           [;[;[;]]]]]

[I had to break this line...]

  This is probably the most complicated parameter... It specifies that

you have some external video hardware (a graphics board), and how to

use it under Linux/m68k. The kernel cannot know more about the hardware

than you tell it here! The kernel also is unable to set or change any

video modes, since it doesn't know about any board internal. So, you

have to switch to that video mode before you start Linux, and cannot

switch to another mode once Linux has started.

  The first 3 parameters of this sub-option should be obvious: ,

 and  give the dimensions of the screen and the number of

planes (depth). The depth is is the logarithm to base 2 of the number

of colors possible. (Or, the other way round: The number of colors is

2^depth).

  You have to tell the kernel furthermore how the video memory is

organized. This is done by a letter as  parameter:

 'n': "normal planes", i.e. one whole plane after another

 'i': "interleaved planes", i.e. 16 bit of the first plane, than 16 bit

      of the next, and so on... This mode is used only with the

          built-in Atari video modes, I think there is no card that

          supports this mode.

 'p': "packed pixels", i.e.  consecutive bits stand for all

          planes of one pixel; this is the most common mode for 8 planes

          (256 colors) on graphic cards

 't': "true color" (more or less packed pixels, but without a color

          lookup table); usually depth is 24

For monochrome modes (i.e.,  is 1), the  letter has a

different meaning:

 'n': normal colors, i.e. 0=white, 1=black

 'i': inverted colors, i.e. 0=black, 1=white

  The next important information about the video hardware is the base

address of the video memory. That is given in the  parameter,

as a hexadecimal number with a "0x" prefix. You have to find out this

address in the documentation of your hardware.

  The next parameter, , tells the kernel about the size of the

video memory. If it's missing, the size is calculated from ,

, and . For now, it is not useful to write a value here.

It would be used only for hardware scrolling (which isn't possible

with the external driver, because the kernel cannot set the video base

address), or for virtual resolutions under X (which the X server

doesn't support yet). So, it's currently best to leave this field

empty, either by ending the "external:" after the video address or by

writing two consecutive semicolons, if you want to give a 

(it is allowed to leave this parameter empty).

  The  parameter is optional. If it is not given, the kernel

cannot read or write any color registers of the video hardware, and

thus you have to set appropriate colors before you start Linux. But if

your card is somehow VGA compatible, you can tell the kernel the base

address of the VGA register set, so it can change the color lookup

table. You have to look up this address in your board's documentation.

To avoid misunderstandings:  is the _base_ address, i.e. a 4k

aligned address. For read/writing the color registers, the kernel

uses the addresses vgabase+0x3c7...vgabase+0x3c9. The 

parameter is written in hexadecimal with a "0x" prefix, just as

.

   is meaningful only if  is specified. It tells the

kernel how wide each of the color register is, i.e. the number of bits

per single color (red/green/blue). Default is 6, another quite usual

value is 8.

  Also  is used together with . It tells the kernel

about the color register model of your gfx board. Currently, the types

"vga" (which is also the default) and "mv300" (SANG MV300) are

implemented.

  Parameter  is required for ProMST or ET4000 cards where

the physical linelength differs from the visible length. With ProMST,

xres_virtual must be set to 2048. For ET4000, xres_virtual depends on the

initialisation of the video-card.

If you're missing a corresponding yres_virtual: the external part is legacy,

therefore we don't support hardware-dependent functions like hardware-scroll,

panning or blanking.

4.1.7) eclock:

--------------

The external pixel clock attached to the Falcon VIDEL shifter. This

currently works only with the ScreenWonder!

4.1.8) monitorcap:

-------------------

Syntax: monitorcap:;;;

This describes the capabilities of a multisync monitor. Don't use it

with a fixed-frequency monitor! For now, only the Falcon frame buffer

uses the settings of "monitorcap:".

   and  are the minimum and maximum, resp., vertical frequencies

your monitor can work with, in Hz.  and  are the same for

the horizontal frequency, in kHz.

  The defaults are 58;62;31;32 (VGA compatible).

  The defaults for TV/SC1224/SC1435 cover both PAL and NTSC standards.

4.1.9) keep

------------

If this option is given, the framebuffer device doesn't do any video

mode calculations and settings on its own. The only Atari fb device

that does this currently is the Falcon.

  What you reach with this: Settings for unknown video extensions

aren't overridden by the driver, so you can still use the mode found

when booting, when the driver doesn't know to set this mode itself.

But this also means, that you can't switch video modes anymore...

  An example where you may want to use "keep" is the ScreenBlaster for

the Falcon.

4.2) atamouse=

--------------

Syntax: atamouse=,[]

  With this option, you can set the mouse movement reporting threshold.

This is the number of pixels of mouse movement that have to accumulate

before the IKBD sends a new mouse packet to the kernel. Higher values

reduce the mouse interrupt load and thus reduce the chance of keyboard

overruns. Lower values give a slightly faster mouse responses and

slightly better mouse tracking.

  You can set the threshold in x and y separately, but usually this is

of little practical use. If there's just one number in the option, it

is used for both dimensions. The default value is 2 for both

thresholds.

4.3) ataflop=

-------------

Syntax: ataflop=[,[,[,]]]

   The drive type may be 0, 1, or 2, for DD, HD, and ED, resp. This

   setting affects how many buffers are reserved and which formats are

   probed (see also below). The default is 1 (HD). Only one drive type

   can be selected. If you have two disk drives, select the "better"

   type.

   The second parameter  tells the kernel whether to use

   track buffering (1) or not (0). The default is machine-dependent:

   no for the Medusa and yes for all others.

   With the two following parameters, you can change the default

   steprate used for drive A and B, resp.

4.4) atascsi=

-------------

Syntax: atascsi=[,[,[,[,]]]]

  This option sets some parameters for the Atari native SCSI driver.

Generally, any number of arguments can be omitted from the end. And

for each of the numbers, a negative value means "use default". The

defaults depend on whether TT-style or Falcon-style SCSI is used.

Below, defaults are noted as n/m, where the first value refers to

TT-SCSI and the latter to Falcon-SCSI. If an illegal value is given

for one parameter, an error message is printed and that one setting is

ignored (others aren't affected).

  :

    This is the maximum number of SCSI commands queued internally to the

    Atari SCSI driver. A value of 1 effectively turns off the driver

    internal multitasking (if it causes problems). Legal values are >=

    1.  can be as high as you like, but values greater than

     times the number of SCSI targets (LUNs) you have

    don't make sense. Default: 16/8.

  :

    Maximum number of SCSI commands issued to the driver for one

    logical unit (LUN, usually one SCSI target). Legal values start

    from 1. If tagged queuing (see below) is not used, values greater

    than 2 don't make sense, but waste memory. Otherwise, the maximum

    is the number of command tags available to the driver (currently

    32). Default: 8/1. (Note: Values > 1 seem to cause problems on a

    Falcon, cause not yet known.)

      The  value at a great part determines the amount of

    memory SCSI reserves for itself. The formula is rather

    complicated, but I can give you some hints:

      no scatter-gather  : cmd_per_lun * 232 bytes

      full scatter-gather: cmd_per_lun * approx. 17 Kbytes

  :

    Size of the scatter-gather table, i.e. the number of requests

    consecutive on the disk that can be merged into one SCSI command.

    Legal values are between 0 and 255. Default: 255/0. Note: This

    value is forced to 0 on a Falcon, since scatter-gather isn't

    possible with the ST-DMA. Not using scatter-gather hurts

    performance significantly.

  :

    The SCSI ID to be used by the initiator (your Atari). This is

    usually 7, the highest possible ID. Every ID on the SCSI bus must

    be unique. Default: determined at run time: If the NV-RAM checksum

    is valid, and bit 7 in byte 30 of the NV-RAM is set, the lower 3

    bits of this byte are used as the host ID. (This method is defined

    by Atari and also used by some TOS HD drivers.) If the above

    isn't given, the default ID is 7. (both, TT and Falcon).

  :

    use tagged queuing for targets that support it. Default: currently

    off, but this may change when tagged queuing handling has been

    proved to be reliable.

    Tagged queuing means that more than one command can be issued to

    one LUN, and the SCSI device itself orders the requests so they

    can be performed in optimal order. Not all SCSI devices support

    tagged queuing (:-().

4.6 switches=

-------------

Syntax: switches=

  With this option you can switch some hardware lines that are often

used to enable/disable certain hardware extensions. Examples are

OverScan, overclocking, ...

  The  is a comma-separated list of the following

items:

  ikbd: set RTS of the keyboard ACIA high

  midi: set RTS of the MIDI ACIA high

  snd6: set bit 6 of the PSG port A

  snd7: set bit 6 of the PSG port A

It doesn't make sense to mention a switch more than once (no

difference to only once), but you can give as many switches as you

want to enable different features. The switch lines are set as early

as possible during kernel initialization (even before determining the

present hardware.)

  All of the items can also be prefixed with "ov_", i.e. "ov_ikbd",

"ov_midi", ... These options are meant for switching on an OverScan

video extension. The difference to the bare option is that the

switch-on is done after video initialization, and somehow synchronized

to the HBLANK. A speciality is that ov_ikbd and ov_midi are switched

off before rebooting, so that OverScan is disabled and TOS boots

correctly.

  If you give an option both, with and without the "ov_" prefix, the

earlier initialization ("ov_"-less) takes precedence. But the

switching-off on reset still happens in this case.

4.5) stram_swap=

----------------

Syntax: stram_swap=[,]

  This option is available only if the kernel has been compiled with

CONFIG_STRAM_SWAP enabled. Normally, the kernel then determines

dynamically whether to actually use ST-RAM as swap space. (Currently,

the fraction of ST-RAM must be less or equal 1/3 of total memory to

enable this swapping.) You can override the kernel's decision by

specifying this option. 1 for  means always enable the swap,

even if you have less alternate RAM. 0 stands for never swap to

ST-RAM, even if it's small enough compared to the rest of memory.

  If ST-RAM swapping is enabled, the kernel usually uses all free

ST-RAM as swap "device". If the kernel resides in ST-RAM, the region

allocated by it is obviously never used for swapping :-) You can also

limit this amount by specifying the second parameter, , if

you want to use parts of ST-RAM as normal system memory.  is

in kBytes and the number should be a multiple of 4 (otherwise: rounded

down).

5) Options for Amiga Only:

==========================

5.1) video=

-----------

Syntax: video=:

The  parameter specifies the name of the frame buffer, valid

options are `amifb', `cyber', 'virge', `retz3' and `clgen', provided

that the respective frame buffer devices have been compiled into the

kernel (or compiled as loadable modules). The behavior of the 

option was changed in 2.1.57 so it is now recommended to specify this

option.

The  is a comma-separated list of the sub-options listed

below. This option is organized similar to the Atari version of the

"video"-option (4.1), but knows fewer sub-options.

5.1.1) video mode

-----------------

Again, similar to the video mode for the Atari (see 4.1.1). Predefined

modes depend on the used frame buffer device.

OCS, ECS and AGA machines all use the color frame buffer. The following

predefined video modes are available:

NTSC modes:

 - ntsc            : 640x200, 15 kHz, 60 Hz

 - ntsc-lace       : 640x400, 15 kHz, 60 Hz interlaced

PAL modes:

 - pal             : 640x256, 15 kHz, 50 Hz

 - pal-lace        : 640x512, 15 kHz, 50 Hz interlaced

ECS modes:

 - multiscan       : 640x480, 29 kHz, 57 Hz

 - multiscan-lace  : 640x960, 29 kHz, 57 Hz interlaced

 - euro36          : 640x200, 15 kHz, 72 Hz

 - euro36-lace     : 640x400, 15 kHz, 72 Hz interlaced

 - euro72          : 640x400, 29 kHz, 68 Hz

 - euro72-lace     : 640x800, 29 kHz, 68 Hz interlaced

 - super72         : 800x300, 23 kHz, 70 Hz

 - super72-lace    : 800x600, 23 kHz, 70 Hz interlaced

 - dblntsc-ff      : 640x400, 27 kHz, 57 Hz

 - dblntsc-lace    : 640x800, 27 kHz, 57 Hz interlaced

 - dblpal-ff       : 640x512, 27 kHz, 47 Hz

 - dblpal-lace     : 640x1024, 27 kHz, 47 Hz interlaced

 - dblntsc         : 640x200, 27 kHz, 57 Hz doublescan

 - dblpal          : 640x256, 27 kHz, 47 Hz doublescan

VGA modes:

 - vga             : 640x480, 31 kHz, 60 Hz

 - vga70           : 640x400, 31 kHz, 70 Hz

Please notice that the ECS and VGA modes require either an ECS or AGA

chipset, and that these modes are limited to 2-bit color for the ECS

chipset and 8-bit color for the AGA chipset.

5.1.2) depth

------------

Syntax: depth:

Specify the number of bit-planes for the selected video-mode.

5.1.3) inverse

--------------

Use inverted display (black on white). Functionally the same as the

"inverse" sub-option for the Atari.

5.1.4) font

-----------

Syntax: font:

Specify the font to use in text modes. Functionally the same as the

"font" sub-option for the Atari, except that `PEARL8x8' is used instead

of `VGA8x8' if the vertical size of the display is less than 400 pixel

rows.

5.1.5) monitorcap:

-------------------

Syntax: monitorcap:;;;

This describes the capabilities of a multisync monitor. For now, only

the color frame buffer uses the settings of "monitorcap:".

   and  are the minimum and maximum, resp., vertical frequencies

your monitor can work with, in Hz.  and  are the same for

the horizontal frequency, in kHz.

  The defaults are 50;90;15;38 (Generic Amiga multisync monitor).

5.2) fd_def_df0=

----------------

Syntax: fd_def_df0=

Sets the df0 value for "silent" floppy drives. The value should be in

hexadecimal with "0x" prefix.

5.3) wd33c93=

-------------

Syntax: wd33c93=

These options affect the A590/A2091, A3000 and GVP Series II SCSI

controllers.

The  is a comma-separated list of the sub-options listed

below.

5.3.1) nosync

-------------

Syntax: nosync:bitmask

  bitmask is a byte where the 1st 7 bits correspond with the 7

possible SCSI devices. Set a bit to prevent sync negotiation on that

device. To maintain backwards compatibility, a command-line such as

"wd33c93=255" will be automatically translated to

"wd33c93=nosync:0xff". The default is to disable sync negotiation for

all devices, eg. nosync:0xff.

5.3.2) period

-------------

Syntax: period:ns

  `ns' is the minimum # of nanoseconds in a SCSI data transfer

period. Default is 500; acceptable values are 250 - 1000.

5.3.3) disconnect

-----------------

Syntax: disconnect:x

  Specify x = 0 to never allow disconnects, 2 to always allow them.

x = 1 does 'adaptive' disconnects, which is the default and generally

the best choice.

5.3.4) debug

------------

Syntax: debug:x

  If `DEBUGGING_ON' is defined, x is a bit mask that causes various

types of debug output to printed - see the DB_xxx defines in

wd33c93.h.

5.3.5) clock

------------

Syntax: clock:x

  x = clock input in MHz for WD33c93 chip. Normal values would be from

8 through 20. The default value depends on your hostadapter(s),

default for the A3000 internal controller is 14, for the A2091 it's 8

and for the GVP hostadapters it's either 8 or 14, depending on the

hostadapter and the SCSI-clock jumper present on some GVP

hostadapters.

5.3.6) next

-----------

  No argument. Used to separate blocks of keywords when there's more

than one wd33c93-based host adapter in the system.

5.3.7) nodma

------------

Syntax: nodma:x

  If x is 1 (or if the option is just written as "nodma"), the WD33c93

controller will not use DMA (= direct memory access) to access the

Amiga's memory.  This is useful for some systems (like A3000's and

A4000's with the A3640 accelerator, revision 3.0) that have problems

using DMA to chip memory.  The default is 0, i.e. to use DMA if

possible.

5.4) gvp11=

-----------

Syntax: gvp11=

  The earlier versions of the GVP driver did not handle DMA

address-mask settings correctly which made it necessary for some

people to use this option, in order to get their GVP controller

running under Linux. These problems have hopefully been solved and the

use of this option is now highly unrecommended!

  Incorrect use can lead to unpredictable behavior, so please only use

this option if you *know* what you are doing and have a reason to do

so. In any case if you experience problems and need to use this

option, please inform us about it by mailing to the Linux/68k kernel

mailing list.

  The address mask set by this option specifies which addresses are

valid for DMA with the GVP Series II SCSI controller. An address is

valid, if no bits are set except the bits that are set in the mask,

too.

  Some versions of the GVP can only DMA into a 24 bit address range,

some can address a 25 bit address range while others can use the whole

32 bit address range for DMA. The correct setting depends on your

controller and should be autodetected by the driver. An example is the

24 bit region which is specified by a mask of 0x00fffffe.

5.5) 53c7xx=

------------

Syntax: 53c7xx=

These options affect the A4000T, A4091, WarpEngine, Blizzard 603e+,

and GForce 040/060 SCSI controllers on the Amiga, as well as the

builtin MVME 16x SCSI controller.

The  is a comma-separated list of the sub-options listed

below.

5.5.1) nosync

-------------

Syntax: nosync:0

  Disables sync negotiation for all devices.  Any value after the

  colon is acceptable (and has the same effect).

5.5.2) noasync

--------------