linux/Documentation/m68k/kernel-options.txt
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   3                                  Command Line Options for Linux/m68k
   4                                  ===================================
   5
   6Last Update: 2 May 1999
   7Linux/m68k version: 2.2.6
   8Author: Roman.Hodek@informatik.uni-erlangen.de (Roman Hodek)
   9Update: jds@kom.auc.dk (Jes Sorensen) and faq@linux-m68k.org (Chris Lawrence)
  10
  110) Introduction
  12===============
  13
  14  Often I've been asked which command line options the Linux/m68k
  15kernel understands, or how the exact syntax for the ... option is, or
  16... about the option ... . I hope, this document supplies all the
  17answers...
  18
  19  Note that some options might be outdated, their descriptions being
  20incomplete or missing. Please update the information and send in the
  21patches.
  22
  23
  241) Overview of the Kernel's Option Processing
  25=============================================
  26
  27The kernel knows three kinds of options on its command line:
  28
  29  1) kernel options
  30  2) environment settings
  31  3) arguments for init
  32
  33To which of these classes an argument belongs is determined as
  34follows: If the option is known to the kernel itself, i.e. if the name
  35(the part before the '=') or, in some cases, the whole argument string
  36is known to the kernel, it belongs to class 1. Otherwise, if the
  37argument contains an '=', it is of class 2, and the definition is put
  38into init's environment. All other arguments are passed to init as
  39command line options.
  40
  41  This document describes the valid kernel options for Linux/m68k in
  42the version mentioned at the start of this file. Later revisions may
  43add new such options, and some may be missing in older versions.
  44
  45  In general, the value (the part after the '=') of an option is a
  46list of values separated by commas. The interpretation of these values
  47is up to the driver that "owns" the option. This association of
  48options with drivers is also the reason that some are further
  49subdivided.
  50
  51
  522) General Kernel Options
  53=========================
  54
  552.1) root=
  56----------
  57
  58Syntax: root=/dev/<device>
  59    or: root=<hex_number>
  60
  61This tells the kernel which device it should mount as the root
  62filesystem. The device must be a block device with a valid filesystem
  63on it.
  64
  65  The first syntax gives the device by name. These names are converted
  66into a major/minor number internally in the kernel in an unusual way.
  67Normally, this "conversion" is done by the device files in /dev, but
  68this isn't possible here, because the root filesystem (with /dev)
  69isn't mounted yet... So the kernel parses the name itself, with some
  70hardcoded name to number mappings. The name must always be a
  71combination of two or three letters, followed by a decimal number.
  72Valid names are:
  73
  74  /dev/ram: -> 0x0100 (initial ramdisk)
  75  /dev/hda: -> 0x0300 (first IDE disk)
  76  /dev/hdb: -> 0x0340 (second IDE disk)
  77  /dev/sda: -> 0x0800 (first SCSI disk)
  78  /dev/sdb: -> 0x0810 (second SCSI disk)
  79  /dev/sdc: -> 0x0820 (third SCSI disk)
  80  /dev/sdd: -> 0x0830 (forth SCSI disk)
  81  /dev/sde: -> 0x0840 (fifth SCSI disk)
  82  /dev/fd : -> 0x0200 (floppy disk)
  83
  84  The name must be followed by a decimal number, that stands for the
  85partition number. Internally, the value of the number is just
  86added to the device number mentioned in the table above. The
  87exceptions are /dev/ram and /dev/fd, where /dev/ram refers to an
  88initial ramdisk loaded by your bootstrap program (please consult the
  89instructions for your bootstrap program to find out how to load an
  90initial ramdisk). As of kernel version 2.0.18 you must specify
  91/dev/ram as the root device if you want to boot from an initial
  92ramdisk. For the floppy devices, /dev/fd, the number stands for the
  93floppy drive number (there are no partitions on floppy disks). I.e.,
  94/dev/fd0 stands for the first drive, /dev/fd1 for the second, and so
  95on. Since the number is just added, you can also force the disk format
  96by adding a number greater than 3. If you look into your /dev
  97directory, use can see the /dev/fd0D720 has major 2 and minor 16. You
  98can specify this device for the root FS by writing "root=/dev/fd16" on
  99the kernel command line.
 100
 101[Strange and maybe uninteresting stuff ON]
 102
 103  This unusual translation of device names has some strange
 104consequences: If, for example, you have a symbolic link from /dev/fd
 105to /dev/fd0D720 as an abbreviation for floppy driver #0 in DD format,
 106you cannot use this name for specifying the root device, because the
 107kernel cannot see this symlink before mounting the root FS and it
 108isn't in the table above. If you use it, the root device will not be 
 109set at all, without an error message. Another example: You cannot use a
 110partition on e.g. the sixth SCSI disk as the root filesystem, if you
 111want to specify it by name. This is, because only the devices up to
 112/dev/sde are in the table above, but not /dev/sdf. Although, you can
 113use the sixth SCSI disk for the root FS, but you have to specify the
 114device by number... (see below). Or, even more strange, you can use the
 115fact that there is no range checking of the partition number, and your
 116knowledge that each disk uses 16 minors, and write "root=/dev/sde17"
 117(for /dev/sdf1).
 118
 119[Strange and maybe uninteresting stuff OFF]
 120
 121  If the device containing your root partition isn't in the table
 122above, you can also specify it by major and minor numbers. These are
 123written in hex, with no prefix and no separator between. E.g., if you
 124have a CD with contents appropriate as a root filesystem in the first
 125SCSI CD-ROM drive, you boot from it by "root=0b00". Here, hex "0b" =
 126decimal 11 is the major of SCSI CD-ROMs, and the minor 0 stands for
 127the first of these. You can find out all valid major numbers by
 128looking into include/linux/major.h.
 129
 130In addition to major and minor numbers, if the device containing your
 131root partition uses a partition table format with unique partition
 132identifiers, then you may use them.  For instance,
 133"root=PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF".  It is also
 134possible to reference another partition on the same device using a
 135known partition UUID as the starting point.  For example,
 136if partition 5 of the device has the UUID of
 13700112233-4455-6677-8899-AABBCCDDEEFF then partition 3 may be found as
 138follows:
 139  PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF/PARTNROFF=-2
 140
 141Authoritative information can be found in
 142"Documentation/kernel-parameters.txt".
 143
 144
 1452.2) ro, rw
 146-----------
 147
 148Syntax: ro
 149    or: rw
 150
 151These two options tell the kernel whether it should mount the root
 152filesystem read-only or read-write. The default is read-only, except
 153for ramdisks, which default to read-write.
 154
 155
 1562.3) debug
 157----------
 158
 159Syntax: debug
 160
 161This raises the kernel log level to 10 (the default is 7). This is the
 162same level as set by the "dmesg" command, just that the maximum level
 163selectable by dmesg is 8.
 164
 165
 1662.4) debug=
 167-----------
 168
 169Syntax: debug=<device>
 170
 171This option causes certain kernel messages be printed to the selected
 172debugging device. This can aid debugging the kernel, since the
 173messages can be captured and analyzed on some other machine. Which
 174devices are possible depends on the machine type. There are no checks
 175for the validity of the device name. If the device isn't implemented,
 176nothing happens.
 177
 178  Messages logged this way are in general stack dumps after kernel
 179memory faults or bad kernel traps, and kernel panics. To be exact: all
 180messages of level 0 (panic messages) and all messages printed while
 181the log level is 8 or more (their level doesn't matter). Before stack
 182dumps, the kernel sets the log level to 10 automatically. A level of
 183at least 8 can also be set by the "debug" command line option (see
 1842.3) and at run time with "dmesg -n 8".
 185
 186Devices possible for Amiga:
 187
 188 - "ser": built-in serial port; parameters: 9600bps, 8N1
 189 - "mem": Save the messages to a reserved area in chip mem. After
 190          rebooting, they can be read under AmigaOS with the tool
 191          'dmesg'.
 192
 193Devices possible for Atari:
 194
 195 - "ser1": ST-MFP serial port ("Modem1"); parameters: 9600bps, 8N1
 196 - "ser2": SCC channel B serial port ("Modem2"); parameters: 9600bps, 8N1
 197 - "ser" : default serial port
 198           This is "ser2" for a Falcon, and "ser1" for any other machine
 199 - "midi": The MIDI port; parameters: 31250bps, 8N1
 200 - "par" : parallel port
 201           The printing routine for this implements a timeout for the
 202           case there's no printer connected (else the kernel would
 203           lock up). The timeout is not exact, but usually a few
 204           seconds.
 205
 206
 2072.6) ramdisk_size=
 208-------------
 209
 210Syntax: ramdisk_size=<size>
 211
 212  This option instructs the kernel to set up a ramdisk of the given
 213size in KBytes. Do not use this option if the ramdisk contents are
 214passed by bootstrap! In this case, the size is selected automatically
 215and should not be overwritten.
 216
 217  The only application is for root filesystems on floppy disks, that
 218should be loaded into memory. To do that, select the corresponding
 219size of the disk as ramdisk size, and set the root device to the disk
 220drive (with "root=").
 221
 222
 2232.7) swap=
 2242.8) buff=
 225-----------
 226
 227  I can't find any sign of these options in 2.2.6.
 228
 229
 2303) General Device Options (Amiga and Atari)
 231===========================================
 232
 2333.1) ether=
 234-----------
 235
 236Syntax: ether=[<irq>[,<base_addr>[,<mem_start>[,<mem_end>]]]],<dev-name>
 237
 238  <dev-name> is the name of a net driver, as specified in
 239drivers/net/Space.c in the Linux source. Most prominent are eth0, ...
 240eth3, sl0, ... sl3, ppp0, ..., ppp3, dummy, and lo.
 241
 242  The non-ethernet drivers (sl, ppp, dummy, lo) obviously ignore the
 243settings by this options. Also, the existing ethernet drivers for
 244Linux/m68k (ariadne, a2065, hydra) don't use them because Zorro boards
 245are really Plug-'n-Play, so the "ether=" option is useless altogether
 246for Linux/m68k.
 247
 248
 2493.2) hd=
 250--------
 251
 252Syntax: hd=<cylinders>,<heads>,<sectors>
 253
 254  This option sets the disk geometry of an IDE disk. The first hd=
 255option is for the first IDE disk, the second for the second one.
 256(I.e., you can give this option twice.) In most cases, you won't have
 257to use this option, since the kernel can obtain the geometry data
 258itself. It exists just for the case that this fails for one of your
 259disks.
 260
 261
 2623.3) max_scsi_luns=
 263-------------------
 264
 265Syntax: max_scsi_luns=<n>
 266
 267  Sets the maximum number of LUNs (logical units) of SCSI devices to
 268be scanned. Valid values for <n> are between 1 and 8. Default is 8 if
 269"Probe all LUNs on each SCSI device" was selected during the kernel
 270configuration, else 1.
 271
 272
 2733.4) st=
 274--------
 275
 276Syntax: st=<buffer_size>,[<write_thres>,[<max_buffers>]]
 277
 278  Sets several parameters of the SCSI tape driver. <buffer_size> is
 279the number of 512-byte buffers reserved for tape operations for each
 280device. <write_thres> sets the number of blocks which must be filled
 281to start an actual write operation to the tape. Maximum value is the
 282total number of buffers. <max_buffer> limits the total number of
 283buffers allocated for all tape devices.
 284
 285
 2863.5) dmasound=
 287--------------
 288
 289Syntax: dmasound=[<buffers>,<buffer-size>[,<catch-radius>]]
 290
 291  This option controls some configurations of the Linux/m68k DMA sound
 292driver (Amiga and Atari): <buffers> is the number of buffers you want
 293to use (minimum 4, default 4), <buffer-size> is the size of each
 294buffer in kilobytes (minimum 4, default 32) and <catch-radius> says
 295how much percent of error will be tolerated when setting a frequency
 296(maximum 10, default 0). For example with 3% you can play 8000Hz
 297AU-Files on the Falcon with its hardware frequency of 8195Hz and thus
 298don't need to expand the sound.
 299
 300
 301
 3024) Options for Atari Only
 303=========================
 304
 3054.1) video=
 306-----------
 307
 308Syntax: video=<fbname>:<sub-options...>
 309
 310The <fbname> parameter specifies the name of the frame buffer,
 311eg. most atari users will want to specify `atafb' here. The
 312<sub-options> is a comma-separated list of the sub-options listed
 313below.
 314
 315NB: Please notice that this option was renamed from `atavideo' to
 316    `video' during the development of the 1.3.x kernels, thus you
 317    might need to update your boot-scripts if upgrading to 2.x from
 318    an 1.2.x kernel.
 319
 320NBB: The behavior of video= was changed in 2.1.57 so the recommended
 321option is to specify the name of the frame buffer.
 322
 3234.1.1) Video Mode
 324-----------------
 325
 326This sub-option may be any of the predefined video modes, as listed
 327in atari/atafb.c in the Linux/m68k source tree. The kernel will
 328activate the given video mode at boot time and make it the default
 329mode, if the hardware allows. Currently defined names are:
 330
 331 - stlow           : 320x200x4
 332 - stmid, default5 : 640x200x2
 333 - sthigh, default4: 640x400x1
 334 - ttlow           : 320x480x8, TT only
 335 - ttmid, default1 : 640x480x4, TT only
 336 - tthigh, default2: 1280x960x1, TT only
 337 - vga2            : 640x480x1, Falcon only
 338 - vga4            : 640x480x2, Falcon only
 339 - vga16, default3 : 640x480x4, Falcon only
 340 - vga256          : 640x480x8, Falcon only
 341 - falh2           : 896x608x1, Falcon only
 342 - falh16          : 896x608x4, Falcon only
 343
 344  If no video mode is given on the command line, the kernel tries the
 345modes names "default<n>" in turn, until one is possible with the
 346hardware in use.
 347
 348  A video mode setting doesn't make sense, if the external driver is
 349activated by a "external:" sub-option.
 350
 3514.1.2) inverse
 352--------------
 353
 354Invert the display. This affects both, text (consoles) and graphics
 355(X) display. Usually, the background is chosen to be black. With this
 356option, you can make the background white.
 357
 3584.1.3) font
 359-----------
 360
 361Syntax: font:<fontname>
 362
 363Specify the font to use in text modes. Currently you can choose only
 364between `VGA8x8', `VGA8x16' and `PEARL8x8'. `VGA8x8' is default, if the
 365vertical size of the display is less than 400 pixel rows. Otherwise, the
 366`VGA8x16' font is the default.
 367
 3684.1.4) hwscroll_
 369----------------
 370
 371Syntax: hwscroll_<n>
 372
 373The number of additional lines of video memory to reserve for
 374speeding up the scrolling ("hardware scrolling"). Hardware scrolling
 375is possible only if the kernel can set the video base address in steps
 376fine enough. This is true for STE, MegaSTE, TT, and Falcon. It is not
 377possible with plain STs and graphics cards (The former because the
 378base address must be on a 256 byte boundary there, the latter because
 379the kernel doesn't know how to set the base address at all.)
 380
 381  By default, <n> is set to the number of visible text lines on the
 382display. Thus, the amount of video memory is doubled, compared to no
 383hardware scrolling. You can turn off the hardware scrolling altogether
 384by setting <n> to 0.
 385
 3864.1.5) internal:
 387----------------
 388
 389Syntax: internal:<xres>;<yres>[;<xres_max>;<yres_max>;<offset>]
 390
 391This option specifies the capabilities of some extended internal video
 392hardware, like e.g. OverScan. <xres> and <yres> give the (extended)
 393dimensions of the screen.
 394
 395  If your OverScan needs a black border, you have to write the last
 396three arguments of the "internal:". <xres_max> is the maximum line
 397length the hardware allows, <yres_max> the maximum number of lines.
 398<offset> is the offset of the visible part of the screen memory to its
 399physical start, in bytes.
 400
 401  Often, extended interval video hardware has to be activated somehow.
 402For this, see the "sw_*" options below.
 403
 4044.1.6) external:
 405----------------
 406
 407Syntax:
 408  external:<xres>;<yres>;<depth>;<org>;<scrmem>[;<scrlen>[;<vgabase>\
 409           [;<colw>[;<coltype>[;<xres_virtual>]]]]]
 410
 411[I had to break this line...]
 412
 413  This is probably the most complicated parameter... It specifies that
 414you have some external video hardware (a graphics board), and how to
 415use it under Linux/m68k. The kernel cannot know more about the hardware
 416than you tell it here! The kernel also is unable to set or change any
 417video modes, since it doesn't know about any board internal. So, you
 418have to switch to that video mode before you start Linux, and cannot
 419switch to another mode once Linux has started.
 420
 421  The first 3 parameters of this sub-option should be obvious: <xres>,
 422<yres> and <depth> give the dimensions of the screen and the number of
 423planes (depth). The depth is the logarithm to base 2 of the number
 424of colors possible. (Or, the other way round: The number of colors is
 4252^depth).
 426
 427  You have to tell the kernel furthermore how the video memory is
 428organized. This is done by a letter as <org> parameter:
 429
 430 'n': "normal planes", i.e. one whole plane after another
 431 'i': "interleaved planes", i.e. 16 bit of the first plane, than 16 bit
 432      of the next, and so on... This mode is used only with the
 433          built-in Atari video modes, I think there is no card that
 434          supports this mode.
 435 'p': "packed pixels", i.e. <depth> consecutive bits stand for all
 436          planes of one pixel; this is the most common mode for 8 planes
 437          (256 colors) on graphic cards
 438 't': "true color" (more or less packed pixels, but without a color
 439          lookup table); usually depth is 24
 440
 441For monochrome modes (i.e., <depth> is 1), the <org> letter has a
 442different meaning:
 443
 444 'n': normal colors, i.e. 0=white, 1=black
 445 'i': inverted colors, i.e. 0=black, 1=white
 446
 447  The next important information about the video hardware is the base
 448address of the video memory. That is given in the <scrmem> parameter,
 449as a hexadecimal number with a "0x" prefix. You have to find out this
 450address in the documentation of your hardware.
 451
 452  The next parameter, <scrlen>, tells the kernel about the size of the
 453video memory. If it's missing, the size is calculated from <xres>,
 454<yres>, and <depth>. For now, it is not useful to write a value here.
 455It would be used only for hardware scrolling (which isn't possible
 456with the external driver, because the kernel cannot set the video base
 457address), or for virtual resolutions under X (which the X server
 458doesn't support yet). So, it's currently best to leave this field
 459empty, either by ending the "external:" after the video address or by
 460writing two consecutive semicolons, if you want to give a <vgabase>
 461(it is allowed to leave this parameter empty).
 462
 463  The <vgabase> parameter is optional. If it is not given, the kernel
 464cannot read or write any color registers of the video hardware, and
 465thus you have to set appropriate colors before you start Linux. But if
 466your card is somehow VGA compatible, you can tell the kernel the base
 467address of the VGA register set, so it can change the color lookup
 468table. You have to look up this address in your board's documentation.
 469To avoid misunderstandings: <vgabase> is the _base_ address, i.e. a 4k
 470aligned address. For read/writing the color registers, the kernel
 471uses the addresses vgabase+0x3c7...vgabase+0x3c9. The <vgabase>
 472parameter is written in hexadecimal with a "0x" prefix, just as
 473<scrmem>.
 474
 475  <colw> is meaningful only if <vgabase> is specified. It tells the
 476kernel how wide each of the color register is, i.e. the number of bits
 477per single color (red/green/blue). Default is 6, another quite usual
 478value is 8.
 479
 480  Also <coltype> is used together with <vgabase>. It tells the kernel
 481about the color register model of your gfx board. Currently, the types
 482"vga" (which is also the default) and "mv300" (SANG MV300) are
 483implemented.
 484
 485  Parameter <xres_virtual> is required for ProMST or ET4000 cards where
 486the physical linelength differs from the visible length. With ProMST, 
 487xres_virtual must be set to 2048. For ET4000, xres_virtual depends on the
 488initialisation of the video-card.
 489If you're missing a corresponding yres_virtual: the external part is legacy,
 490therefore we don't support hardware-dependent functions like hardware-scroll,
 491panning or blanking.
 492
 4934.1.7) eclock:
 494--------------
 495
 496The external pixel clock attached to the Falcon VIDEL shifter. This
 497currently works only with the ScreenWonder!
 498
 4994.1.8) monitorcap:
 500-------------------
 501
 502Syntax: monitorcap:<vmin>;<vmax>;<hmin>;<hmax>
 503
 504This describes the capabilities of a multisync monitor. Don't use it
 505with a fixed-frequency monitor! For now, only the Falcon frame buffer
 506uses the settings of "monitorcap:".
 507
 508  <vmin> and <vmax> are the minimum and maximum, resp., vertical frequencies
 509your monitor can work with, in Hz. <hmin> and <hmax> are the same for
 510the horizontal frequency, in kHz.
 511
 512  The defaults are 58;62;31;32 (VGA compatible).
 513
 514  The defaults for TV/SC1224/SC1435 cover both PAL and NTSC standards.
 515
 5164.1.9) keep
 517------------
 518
 519If this option is given, the framebuffer device doesn't do any video
 520mode calculations and settings on its own. The only Atari fb device
 521that does this currently is the Falcon.
 522
 523  What you reach with this: Settings for unknown video extensions
 524aren't overridden by the driver, so you can still use the mode found
 525when booting, when the driver doesn't know to set this mode itself.
 526But this also means, that you can't switch video modes anymore...
 527
 528  An example where you may want to use "keep" is the ScreenBlaster for
 529the Falcon.
 530
 531
 5324.2) atamouse=
 533--------------
 534
 535Syntax: atamouse=<x-threshold>,[<y-threshold>]
 536
 537  With this option, you can set the mouse movement reporting threshold.
 538This is the number of pixels of mouse movement that have to accumulate
 539before the IKBD sends a new mouse packet to the kernel. Higher values
 540reduce the mouse interrupt load and thus reduce the chance of keyboard
 541overruns. Lower values give a slightly faster mouse responses and
 542slightly better mouse tracking.
 543
 544  You can set the threshold in x and y separately, but usually this is
 545of little practical use. If there's just one number in the option, it
 546is used for both dimensions. The default value is 2 for both
 547thresholds.
 548
 549
 5504.3) ataflop=
 551-------------
 552
 553Syntax: ataflop=<drive type>[,<trackbuffering>[,<steprateA>[,<steprateB>]]]
 554
 555   The drive type may be 0, 1, or 2, for DD, HD, and ED, resp. This
 556   setting affects how many buffers are reserved and which formats are
 557   probed (see also below). The default is 1 (HD). Only one drive type
 558   can be selected. If you have two disk drives, select the "better"
 559   type.
 560
 561   The second parameter <trackbuffer> tells the kernel whether to use
 562   track buffering (1) or not (0). The default is machine-dependent:
 563   no for the Medusa and yes for all others.
 564
 565   With the two following parameters, you can change the default
 566   steprate used for drive A and B, resp. 
 567
 568
 5694.4) atascsi=
 570-------------
 571
 572Syntax: atascsi=<can_queue>[,<cmd_per_lun>[,<scat-gat>[,<host-id>[,<tagged>]]]]
 573
 574  This option sets some parameters for the Atari native SCSI driver.
 575Generally, any number of arguments can be omitted from the end. And
 576for each of the numbers, a negative value means "use default". The
 577defaults depend on whether TT-style or Falcon-style SCSI is used.
 578Below, defaults are noted as n/m, where the first value refers to
 579TT-SCSI and the latter to Falcon-SCSI. If an illegal value is given
 580for one parameter, an error message is printed and that one setting is
 581ignored (others aren't affected).
 582
 583  <can_queue>:
 584    This is the maximum number of SCSI commands queued internally to the
 585    Atari SCSI driver. A value of 1 effectively turns off the driver
 586    internal multitasking (if it causes problems). Legal values are >=
 587    1. <can_queue> can be as high as you like, but values greater than
 588    <cmd_per_lun> times the number of SCSI targets (LUNs) you have
 589    don't make sense. Default: 16/8.
 590
 591  <cmd_per_lun>:
 592    Maximum number of SCSI commands issued to the driver for one
 593    logical unit (LUN, usually one SCSI target). Legal values start
 594    from 1. If tagged queuing (see below) is not used, values greater
 595    than 2 don't make sense, but waste memory. Otherwise, the maximum
 596    is the number of command tags available to the driver (currently
 597    32). Default: 8/1. (Note: Values > 1 seem to cause problems on a
 598    Falcon, cause not yet known.)
 599
 600      The <cmd_per_lun> value at a great part determines the amount of
 601    memory SCSI reserves for itself. The formula is rather
 602    complicated, but I can give you some hints:
 603      no scatter-gather  : cmd_per_lun * 232 bytes
 604      full scatter-gather: cmd_per_lun * approx. 17 Kbytes
 605
 606  <scat-gat>:
 607    Size of the scatter-gather table, i.e. the number of requests
 608    consecutive on the disk that can be merged into one SCSI command.
 609    Legal values are between 0 and 255. Default: 255/0. Note: This
 610    value is forced to 0 on a Falcon, since scatter-gather isn't
 611    possible with the ST-DMA. Not using scatter-gather hurts
 612    performance significantly.
 613
 614  <host-id>:
 615    The SCSI ID to be used by the initiator (your Atari). This is
 616    usually 7, the highest possible ID. Every ID on the SCSI bus must
 617    be unique. Default: determined at run time: If the NV-RAM checksum
 618    is valid, and bit 7 in byte 30 of the NV-RAM is set, the lower 3
 619    bits of this byte are used as the host ID. (This method is defined
 620    by Atari and also used by some TOS HD drivers.) If the above
 621    isn't given, the default ID is 7. (both, TT and Falcon).
 622
 623  <tagged>:
 624    0 means turn off tagged queuing support, all other values > 0 mean
 625    use tagged queuing for targets that support it. Default: currently
 626    off, but this may change when tagged queuing handling has been
 627    proved to be reliable.
 628
 629    Tagged queuing means that more than one command can be issued to
 630    one LUN, and the SCSI device itself orders the requests so they
 631    can be performed in optimal order. Not all SCSI devices support
 632    tagged queuing (:-().
 633
 6344.5 switches=
 635-------------
 636
 637Syntax: switches=<list of switches>
 638
 639  With this option you can switch some hardware lines that are often
 640used to enable/disable certain hardware extensions. Examples are
 641OverScan, overclocking, ...
 642
 643  The <list of switches> is a comma-separated list of the following
 644items:
 645
 646  ikbd: set RTS of the keyboard ACIA high
 647  midi: set RTS of the MIDI ACIA high
 648  snd6: set bit 6 of the PSG port A
 649  snd7: set bit 6 of the PSG port A
 650
 651It doesn't make sense to mention a switch more than once (no
 652difference to only once), but you can give as many switches as you
 653want to enable different features. The switch lines are set as early
 654as possible during kernel initialization (even before determining the
 655present hardware.)
 656
 657  All of the items can also be prefixed with "ov_", i.e. "ov_ikbd",
 658"ov_midi", ... These options are meant for switching on an OverScan
 659video extension. The difference to the bare option is that the
 660switch-on is done after video initialization, and somehow synchronized
 661to the HBLANK. A speciality is that ov_ikbd and ov_midi are switched
 662off before rebooting, so that OverScan is disabled and TOS boots
 663correctly.
 664
 665  If you give an option both, with and without the "ov_" prefix, the
 666earlier initialization ("ov_"-less) takes precedence. But the
 667switching-off on reset still happens in this case.
 668
 6695) Options for Amiga Only:
 670==========================
 671
 6725.1) video=
 673-----------
 674
 675Syntax: video=<fbname>:<sub-options...>
 676
 677The <fbname> parameter specifies the name of the frame buffer, valid
 678options are `amifb', `cyber', 'virge', `retz3' and `clgen', provided
 679that the respective frame buffer devices have been compiled into the
 680kernel (or compiled as loadable modules). The behavior of the <fbname>
 681option was changed in 2.1.57 so it is now recommended to specify this
 682option.
 683
 684The <sub-options> is a comma-separated list of the sub-options listed
 685below. This option is organized similar to the Atari version of the
 686"video"-option (4.1), but knows fewer sub-options.
 687
 6885.1.1) video mode
 689-----------------
 690
 691Again, similar to the video mode for the Atari (see 4.1.1). Predefined
 692modes depend on the used frame buffer device.
 693
 694OCS, ECS and AGA machines all use the color frame buffer. The following
 695predefined video modes are available:
 696
 697NTSC modes:
 698 - ntsc            : 640x200, 15 kHz, 60 Hz
 699 - ntsc-lace       : 640x400, 15 kHz, 60 Hz interlaced
 700PAL modes:
 701 - pal             : 640x256, 15 kHz, 50 Hz
 702 - pal-lace        : 640x512, 15 kHz, 50 Hz interlaced
 703ECS modes:
 704 - multiscan       : 640x480, 29 kHz, 57 Hz
 705 - multiscan-lace  : 640x960, 29 kHz, 57 Hz interlaced
 706 - euro36          : 640x200, 15 kHz, 72 Hz
 707 - euro36-lace     : 640x400, 15 kHz, 72 Hz interlaced
 708 - euro72          : 640x400, 29 kHz, 68 Hz
 709 - euro72-lace     : 640x800, 29 kHz, 68 Hz interlaced
 710 - super72         : 800x300, 23 kHz, 70 Hz
 711 - super72-lace    : 800x600, 23 kHz, 70 Hz interlaced
 712 - dblntsc-ff      : 640x400, 27 kHz, 57 Hz
 713 - dblntsc-lace    : 640x800, 27 kHz, 57 Hz interlaced
 714 - dblpal-ff       : 640x512, 27 kHz, 47 Hz
 715 - dblpal-lace     : 640x1024, 27 kHz, 47 Hz interlaced
 716 - dblntsc         : 640x200, 27 kHz, 57 Hz doublescan
 717 - dblpal          : 640x256, 27 kHz, 47 Hz doublescan
 718VGA modes:
 719 - vga             : 640x480, 31 kHz, 60 Hz
 720 - vga70           : 640x400, 31 kHz, 70 Hz
 721
 722Please notice that the ECS and VGA modes require either an ECS or AGA
 723chipset, and that these modes are limited to 2-bit color for the ECS
 724chipset and 8-bit color for the AGA chipset.
 725
 7265.1.2) depth
 727------------
 728
 729Syntax: depth:<nr. of bit-planes>
 730
 731Specify the number of bit-planes for the selected video-mode.
 732
 7335.1.3) inverse
 734--------------
 735
 736Use inverted display (black on white). Functionally the same as the
 737"inverse" sub-option for the Atari.
 738
 7395.1.4) font
 740-----------
 741
 742Syntax: font:<fontname>
 743
 744Specify the font to use in text modes. Functionally the same as the
 745"font" sub-option for the Atari, except that `PEARL8x8' is used instead
 746of `VGA8x8' if the vertical size of the display is less than 400 pixel
 747rows.
 748
 7495.1.5) monitorcap:
 750-------------------
 751
 752Syntax: monitorcap:<vmin>;<vmax>;<hmin>;<hmax>
 753
 754This describes the capabilities of a multisync monitor. For now, only
 755the color frame buffer uses the settings of "monitorcap:".
 756
 757  <vmin> and <vmax> are the minimum and maximum, resp., vertical frequencies
 758your monitor can work with, in Hz. <hmin> and <hmax> are the same for
 759the horizontal frequency, in kHz.
 760
 761  The defaults are 50;90;15;38 (Generic Amiga multisync monitor).
 762
 763
 7645.2) fd_def_df0=
 765----------------
 766
 767Syntax: fd_def_df0=<value>
 768
 769Sets the df0 value for "silent" floppy drives. The value should be in
 770hexadecimal with "0x" prefix.
 771
 772
 7735.3) wd33c93=
 774-------------
 775
 776Syntax: wd33c93=<sub-options...>
 777
 778These options affect the A590/A2091, A3000 and GVP Series II SCSI
 779controllers.
 780
 781The <sub-options> is a comma-separated list of the sub-options listed
 782below.
 783
 7845.3.1) nosync
 785-------------
 786
 787Syntax: nosync:bitmask
 788
 789  bitmask is a byte where the 1st 7 bits correspond with the 7
 790possible SCSI devices. Set a bit to prevent sync negotiation on that
 791device. To maintain backwards compatibility, a command-line such as
 792"wd33c93=255" will be automatically translated to
 793"wd33c93=nosync:0xff". The default is to disable sync negotiation for
 794all devices, eg. nosync:0xff.
 795
 7965.3.2) period
 797-------------
 798
 799Syntax: period:ns
 800
 801  `ns' is the minimum # of nanoseconds in a SCSI data transfer
 802period. Default is 500; acceptable values are 250 - 1000.
 803
 8045.3.3) disconnect
 805-----------------
 806
 807Syntax: disconnect:x
 808
 809  Specify x = 0 to never allow disconnects, 2 to always allow them.
 810x = 1 does 'adaptive' disconnects, which is the default and generally
 811the best choice.
 812
 8135.3.4) debug
 814------------
 815
 816Syntax: debug:x
 817
 818  If `DEBUGGING_ON' is defined, x is a bit mask that causes various
 819types of debug output to printed - see the DB_xxx defines in
 820wd33c93.h.
 821
 8225.3.5) clock
 823------------
 824
 825Syntax: clock:x
 826
 827  x = clock input in MHz for WD33c93 chip. Normal values would be from
 8288 through 20. The default value depends on your hostadapter(s),
 829default for the A3000 internal controller is 14, for the A2091 it's 8
 830and for the GVP hostadapters it's either 8 or 14, depending on the
 831hostadapter and the SCSI-clock jumper present on some GVP
 832hostadapters.
 833
 8345.3.6) next
 835-----------
 836
 837  No argument. Used to separate blocks of keywords when there's more
 838than one wd33c93-based host adapter in the system.
 839
 8405.3.7) nodma
 841------------
 842
 843Syntax: nodma:x
 844
 845  If x is 1 (or if the option is just written as "nodma"), the WD33c93
 846controller will not use DMA (= direct memory access) to access the
 847Amiga's memory.  This is useful for some systems (like A3000's and
 848A4000's with the A3640 accelerator, revision 3.0) that have problems
 849using DMA to chip memory.  The default is 0, i.e. to use DMA if
 850possible.
 851
 852
 8535.4) gvp11=
 854-----------
 855
 856Syntax: gvp11=<addr-mask>
 857
 858  The earlier versions of the GVP driver did not handle DMA
 859address-mask settings correctly which made it necessary for some
 860people to use this option, in order to get their GVP controller
 861running under Linux. These problems have hopefully been solved and the
 862use of this option is now highly unrecommended!
 863
 864  Incorrect use can lead to unpredictable behavior, so please only use
 865this option if you *know* what you are doing and have a reason to do
 866so. In any case if you experience problems and need to use this
 867option, please inform us about it by mailing to the Linux/68k kernel
 868mailing list.
 869
 870  The address mask set by this option specifies which addresses are
 871valid for DMA with the GVP Series II SCSI controller. An address is
 872valid, if no bits are set except the bits that are set in the mask,
 873too.
 874
 875  Some versions of the GVP can only DMA into a 24 bit address range,
 876some can address a 25 bit address range while others can use the whole
 87732 bit address range for DMA. The correct setting depends on your
 878controller and should be autodetected by the driver. An example is the
 87924 bit region which is specified by a mask of 0x00fffffe.
 880
 881
 882/* Local Variables: */
 883/* mode: text       */
 884/* End:             */
 885
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