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  19  Note that some options might be outdated, their descriptions being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  /dev/xda: -> 0x0c00 (first XT disk, unused in Linux/m68k)
  84  /dev/xdb: -> 0x0c40 (second XT disk, unused in Linux/m68k)
  85
  86  The name must be followed by a decimal number, that stands for the
  87partition number. Internally, the value of the number is just
  88added to the device number mentioned in the table above. The
  89exceptions are /dev/ram and /dev/fd, where /dev/ram refers to an
  90initial ramdisk loaded by your bootstrap program (please consult the
  91instructions for your bootstrap program to find out how to load an
  92initial ramdisk). As of kernel version 2.0.18 you must specify
  93/dev/ram as the root device if you want to boot from an initial
  94ramdisk. For the floppy devices, /dev/fd, the number stands for the
  95floppy drive number (there are no partitions on floppy disks). I.e.,
  96/dev/fd0 stands for the first drive, /dev/fd1 for the second, and so
  97on. Since the number is just added, you can also force the disk format
  98by adding a number greater than 3. If you look into your /dev
  99directory, use can see the /dev/fd0D720 has major 2 and minor 16. You
 100can specify this device for the root FS by writing "root=/dev/fd16" on
 101the kernel command line.
 102
 103[Strange and maybe uninteresting stuff ON]
 104
 105  This unusual translation of device names has some strange
 106consequences: If, for example, you have a symbolic link from /dev/fd
 107to /dev/fd0D720 as an abbreviation for floppy driver #0 in DD format,
 108you cannot use this name for specifying the root device, because the
 109kernel cannot see this symlink before mounting the root FS and it
 110isn't in the table above. If you use it, the root device will not be 
 111set at all, without an error message. Another example: You cannot use a
 112partition on e.g. the sixth SCSI disk as the root filesystem, if you
 113want to specify it by name. This is, because only the devices up to
 114/dev/sde are in the table above, but not /dev/sdf. Although, you can
 115use the sixth SCSI disk for the root FS, but you have to specify the
 116device by number... (see below). Or, even more strange, you can use the
 117fact that there is no range checking of the partition number, and your
 118knowledge that each disk uses 16 minors, and write "root=/dev/sde17"
 119(for /dev/sdf1).
 120
 121[Strange and maybe uninteresting stuff OFF]
 122
 123  If the device containing your root partition isn't in the table
 124above, you can also specify it by major and minor numbers. These are
 125written in hex, with no prefix and no separator between. E.g., if you
 126have a CD with contents appropriate as a root filesystem in the first
 127SCSI CD-ROM drive, you boot from it by "root=0b00". Here, hex "0b" =
 128decimal 11 is the major of SCSI CD-ROMs, and the minor 0 stands for
 129the first of these. You can find out all valid major numbers by
 130looking into include/linux/major.h.
 131
 132In addition to major and minor numbers, if the device containing your
 133root partition uses a partition table format with unique partition
 134identifiers, then you may use them.  For instance,
 135"root=PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF".  It is also
 136possible to reference another partition on the same device using a
 137known partition UUID as the starting point.  For example,
 138if partition 5 of the device has the UUID of
 13900112233-4455-6677-8899-AABBCCDDEEFF then partition 3 may be found as
 140follows:
 141  PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF/PARTNROFF=-2
 142
 143Authoritative information can be found in
 144"Documentation/kernel-parameters.txt".
 145
 146
 1472.2) ro, rw
 148-----------
 149
 150Syntax: ro
 151    or: rw
 152
 153These two options tell the kernel whether it should mount the root
 154filesystem read-only or read-write. The default is read-only, except
 155for ramdisks, which default to read-write.
 156
 157
 1582.3) debug
 159----------
 160
 161Syntax: debug
 162
 163This raises the kernel log level to 10 (the default is 7). This is the
 164same level as set by the "dmesg" command, just that the maximum level
 165selectable by dmesg is 8.
 166
 167
 1682.4) debug=
 169-----------
 170
 171Syntax: debug=<device>
 172
 173This option causes certain kernel messages be printed to the selected
 174debugging device. This can aid debugging the kernel, since the
 175messages can be captured and analyzed on some other machine. Which
 176devices are possible depends on the machine type. There are no checks
 177for the validity of the device name. If the device isn't implemented,
 178nothing happens.
 179
 180  Messages logged this way are in general stack dumps after kernel
 181memory faults or bad kernel traps, and kernel panics. To be exact: all
 182messages of level 0 (panic messages) and all messages printed while
 183the log level is 8 or more (their level doesn't matter). Before stack
 184dumps, the kernel sets the log level to 10 automatically. A level of
 185at least 8 can also be set by the "debug" command line option (see
 1862.3) and at run time with "dmesg -n 8".
 187
 188Devices possible for Amiga:
 189
 190 - "ser": built-in serial port; parameters: 9600bps, 8N1
 191 - "mem": Save the messages to a reserved area in chip mem. After
 192          rebooting, they can be read under AmigaOS with the tool
 193          'dmesg'.
 194
 195Devices possible for Atari:
 196
 197 - "ser1": ST-MFP serial port ("Modem1"); parameters: 9600bps, 8N1
 198 - "ser2": SCC channel B serial port ("Modem2"); parameters: 9600bps, 8N1
 199 - "ser" : default serial port
 200           This is "ser2" for a Falcon, and "ser1" for any other machine
 201 - "midi": The MIDI port; parameters: 31250bps, 8N1
 202 - "par" : parallel port
 203           The printing routine for this implements a timeout for the
 204           case there's no printer connected (else the kernel would
 205           lock up). The timeout is not exact, but usually a few
 206           seconds.
 207
 208
 2092.6) ramdisk_size=
 210-------------
 211
 212Syntax: ramdisk_size=<size>
 213
 214  This option instructs the kernel to set up a ramdisk of the given
 215size in KBytes. Do not use this option if the ramdisk contents are
 216passed by bootstrap! In this case, the size is selected automatically
 217and should not be overwritten.
 218
 219  The only application is for root filesystems on floppy disks, that
 220should be loaded into memory. To do that, select the corresponding
 221size of the disk as ramdisk size, and set the root device to the disk
 222drive (with "root=").
 223
 224
 2252.7) swap=
 2262.8) buff=
 227-----------
 228
 229  I can't find any sign of these options in 2.2.6.
 230
 231
 2323) General Device Options (Amiga and Atari)
 233===========================================
 234
 2353.1) ether=
 236-----------
 237
 238Syntax: ether=[<irq>[,<base_addr>[,<mem_start>[,<mem_end>]]]],<dev-name>
 239
 240  <dev-name> is the name of a net driver, as specified in
 241drivers/net/Space.c in the Linux source. Most prominent are eth0, ...
 242eth3, sl0, ... sl3, ppp0, ..., ppp3, dummy, and lo.
 243
 244  The non-ethernet drivers (sl, ppp, dummy, lo) obviously ignore the
 245settings by this options. Also, the existing ethernet drivers for
 246Linux/m68k (ariadne, a2065, hydra) don't use them because Zorro boards
 247are really Plug-'n-Play, so the "ether=" option is useless altogether
 248for Linux/m68k.
 249
 250
 2513.2) hd=
 252--------
 253
 254Syntax: hd=<cylinders>,<heads>,<sectors>
 255
 256  This option sets the disk geometry of an IDE disk. The first hd=
 257option is for the first IDE disk, the second for the second one.
 258(I.e., you can give this option twice.) In most cases, you won't have
 259to use this option, since the kernel can obtain the geometry data
 260itself. It exists just for the case that this fails for one of your
 261disks.
 262
 263
 2643.3) max_scsi_luns=
 265-------------------
 266
 267Syntax: max_scsi_luns=<n>
 268
 269  Sets the maximum number of LUNs (logical units) of SCSI devices to
 270be scanned. Valid values for <n> are between 1 and 8. Default is 8 if
 271"Probe all LUNs on each SCSI device" was selected during the kernel
 272configuration, else 1.
 273
 274
 2753.4) st=
 276--------
 277
 278Syntax: st=<buffer_size>,[<write_thres>,[<max_buffers>]]
 279
 280  Sets several parameters of the SCSI tape driver. <buffer_size> is
 281the number of 512-byte buffers reserved for tape operations for each
 282device. <write_thres> sets the number of blocks which must be filled
 283to start an actual write operation to the tape. Maximum value is the
 284total number of buffers. <max_buffer> limits the total number of
 285buffers allocated for all tape devices.
 286
 287
 2883.5) dmasound=
 289--------------
 290
 291Syntax: dmasound=[<buffers>,<buffer-size>[,<catch-radius>]]
 292
 293  This option controls some configurations of the Linux/m68k DMA sound
 294driver (Amiga and Atari): <buffers> is the number of buffers you want
 295to use (minimum 4, default 4), <buffer-size> is the size of each
 296buffer in kilobytes (minimum 4, default 32) and <catch-radius> says
 297how much percent of error will be tolerated when setting a frequency
 298(maximum 10, default 0). For example with 3% you can play 8000Hz
 299AU-Files on the Falcon with its hardware frequency of 8195Hz and thus
 300don't need to expand the sound.
 301
 302
 303
 3044) Options for Atari Only
 305=========================
 306
 3074.1) video=
 308-----------
 309
 310Syntax: video=<fbname>:<sub-options...>
 311
 312The <fbname> parameter specifies the name of the frame buffer,
 313eg. most atari users will want to specify `atafb' here. The
 314<sub-options> is a comma-separated list of the sub-options listed
 315below.
 316
 317NB: Please notice that this option was renamed from `atavideo' to
 318    `video' during the development of the 1.3.x kernels, thus you
 319    might need to update your boot-scripts if upgrading to 2.x from
 320    an 1.2.x kernel.
 321
 322NBB: The behavior of video= was changed in 2.1.57 so the recommended
 323option is to specify the name of the frame buffer.
 324
 3254.1.1) Video Mode
 326-----------------
 327
 328This sub-option may be any of the predefined video modes, as listed
 329in atari/atafb.c in the Linux/m68k source tree. The kernel will
 330activate the given video mode at boot time and make it the default
 331mode, if the hardware allows. Currently defined names are:
 332
 333 - stlow           : 320x200x4
 334 - stmid, default5 : 640x200x2
 335 - sthigh, default4: 640x400x1
 336 - ttlow           : 320x480x8, TT only
 337 - ttmid, default1 : 640x480x4, TT only
 338 - tthigh, default2: 1280x960x1, TT only
 339 - vga2            : 640x480x1, Falcon only
 340 - vga4            : 640x480x2, Falcon only
 341 - vga16, default3 : 640x480x4, Falcon only
 342 - vga256          : 640x480x8, Falcon only
 343 - falh2           : 896x608x1, Falcon only
 344 - falh16          : 896x608x4, Falcon only
 345
 346  If no video mode is given on the command line, the kernel tries the
 347modes names "default<n>" in turn, until one is possible with the
 348hardware in use.
 349
 350  A video mode setting doesn't make sense, if the external driver is
 351activated by a "external:" sub-option.
 352
 3534.1.2) inverse
 354--------------
 355
 356Invert the display. This affects both, text (consoles) and graphics
 357(X) display. Usually, the background is chosen to be black. With this
 358option, you can make the background white.
 359
 3604.1.3) font
 361-----------
 362
 363Syntax: font:<fontname>
 364
 365Specify the font to use in text modes. Currently you can choose only
 366between `VGA8x8', `VGA8x16' and `PEARL8x8'. `VGA8x8' is default, if the
 367vertical size of the display is less than 400 pixel rows. Otherwise, the
 368`VGA8x16' font is the default.
 369
 3704.1.4) hwscroll_
 371----------------
 372
 373Syntax: hwscroll_<n>
 374
 375The number of additional lines of video memory to reserve for
 376speeding up the scrolling ("hardware scrolling"). Hardware scrolling
 377is possible only if the kernel can set the video base address in steps
 378fine enough. This is true for STE, MegaSTE, TT, and Falcon. It is not
 379possible with plain STs and graphics cards (The former because the
 380base address must be on a 256 byte boundary there, the latter because
 381the kernel doesn't know how to set the base address at all.)
 382
 383  By default, <n> is set to the number of visible text lines on the
 384display. Thus, the amount of video memory is doubled, compared to no
 385hardware scrolling. You can turn off the hardware scrolling altogether
 386by setting <n> to 0.
 387
 3884.1.5) internal:
 389----------------
 390
 391Syntax: internal:<xres>;<yres>[;<xres_max>;<yres_max>;<offset>]
 392
 393This option specifies the capabilities of some extended internal video
 394hardware, like e.g. OverScan. <xres> and <yres> give the (extended)
 395dimensions of the screen.
 396
 397  If your OverScan needs a black border, you have to write the last
 398three arguments of the "internal:". <xres_max> is the maximum line
 399length the hardware allows, <yres_max> the maximum number of lines.
 400<offset> is the offset of the visible part of the screen memory to its
 401physical start, in bytes.
 402
 403  Often, extended interval video hardware has to be activated somehow.
 404For this, see the "sw_*" options below.
 405
 4064.1.6) external:
 407----------------
 408
 409Syntax:
 410  external:<xres>;<yres>;<depth>;<org>;<scrmem>[;<scrlen>[;<vgabase>\
 411           [;<colw>[;<coltype>[;<xres_virtual>]]]]]
 412
 413[I had to break this line...]
 414
 415  This is probably the most complicated parameter... It specifies that
 416you have some external video hardware (a graphics board), and how to
 417use it under Linux/m68k. The kernel cannot know more about the hardware
 418than you tell it here! The kernel also is unable to set or change any
 419video modes, since it doesn't know about any board internal. So, you
 420have to switch to that video mode before you start Linux, and cannot
 421switch to another mode once Linux has started.
 422
 423  The first 3 parameters of this sub-option should be obvious: <xres>,
 424<yres> and <depth> give the dimensions of the screen and the number of
 425planes (depth). The depth is the logarithm to base 2 of the number
 426of colors possible. (Or, the other way round: The number of colors is
 4272^depth).
 428
 429  You have to tell the kernel furthermore how the video memory is
 430organized. This is done by a letter as <org> parameter:
 431
 432 'n': "normal planes", i.e. one whole plane after another
 433 'i': "interleaved planes", i.e. 16 bit of the first plane, than 16 bit
 434      of the next, and so on... This mode is used only with the
 435          built-in Atari video modes, I think there is no card that
 436          supports this mode.
 437 'p': "packed pixels", i.e. <depth> consecutive bits stand for all
 438          planes of one pixel; this is the most common mode for 8 planes
 439          (256 colors) on graphic cards
 440 't': "true color" (more or less packed pixels, but without a color
 441          lookup table); usually depth is 24
 442
 443For monochrome modes (i.e., <depth> is 1), the <org> letter has a
 444different meaning:
 445
 446 'n': normal colors, i.e. 0=white, 1=black
 447 'i': inverted colors, i.e. 0=black, 1=white
 448
 449  The next important information about the video hardware is the base
 450address of the video memory. That is given in the <scrmem> parameter,
 451as a hexadecimal number with a "0x" prefix. You have to find out this
 452address in the documentation of your hardware.
 453
 454  The next parameter, <scrlen>, tells the kernel about the size of the
 455video memory. If it's missing, the size is calculated from <xres>,
 456<yres>, and <depth>. For now, it is not useful to write a value here.
 457It would be used only for hardware scrolling (which isn't possible
 458with the external driver, because the kernel cannot set the video base
 459address), or for virtual resolutions under X (which the X server
 460doesn't support yet). So, it's currently best to leave this field
 461empty, either by ending the "external:" after the video address or by
 462writing two consecutive semicolons, if you want to give a <vgabase>
 463(it is allowed to leave this parameter empty).
 464
 465  The <vgabase> parameter is optional. If it is not given, the kernel
 466cannot read or write any color registers of the video hardware, and
 467thus you have to set appropriate colors before you start Linux. But if
 468your card is somehow VGA compatible, you can tell the kernel the base
 469address of the VGA register set, so it can change the color lookup
 470table. You have to look up this address in your board's documentation.
 471To avoid misunderstandings: <vgabase> is the _base_ address, i.e. a 4k
 472aligned address. For read/writing the color registers, the kernel
 473uses the addresses vgabase+0x3c7...vgabase+0x3c9. The <vgabase>
 474parameter is written in hexadecimal with a "0x" prefix, just as
 475<scrmem>.
 476
 477  <colw> is meaningful only if <vgabase> is specified. It tells the
 478kernel how wide each of the color register is, i.e. the number of bits
 479per single color (red/green/blue). Default is 6, another quite usual
 480value is 8.
 481
 482  Also <coltype> is used together with <vgabase>. It tells the kernel
 483about the color register model of your gfx board. Currently, the types
 484"vga" (which is also the default) and "mv300" (SANG MV300) are
 485implemented.
 486
 487  Parameter <xres_virtual> is required for ProMST or ET4000 cards where
 488the physical linelength differs from the visible length. With ProMST, 
 489xres_virtual must be set to 2048. For ET4000, xres_virtual depends on the
 490initialisation of the video-card.
 491If you're missing a corresponding yres_virtual: the external part is legacy,
 492therefore we don't support hardware-dependent functions like hardware-scroll,
 493panning or blanking.
 494
 4954.1.7) eclock:
 496--------------
 497
 498The external pixel clock attached to the Falcon VIDEL shifter. This
 499currently works only with the ScreenWonder!
 500
 5014.1.8) monitorcap:
 502-------------------
 503
 504Syntax: monitorcap:<vmin>;<vmax>;<hmin>;<hmax>
 505
 506This describes the capabilities of a multisync monitor. Don't use it
 507with a fixed-frequency monitor! For now, only the Falcon frame buffer
 508uses the settings of "monitorcap:".
 509
 510  <vmin> and <vmax> are the minimum and maximum, resp., vertical frequencies
 511your monitor can work with, in Hz. <hmin> and <hmax> are the same for
 512the horizontal frequency, in kHz.
 513
 514  The defaults are 58;62;31;32 (VGA compatible).
 515
 516  The defaults for TV/SC1224/SC1435 cover both PAL and NTSC standards.
 517
 5184.1.9) keep
 519------------
 520
 521If this option is given, the framebuffer device doesn't do any video
 522mode calculations and settings on its own. The only Atari fb device
 523that does this currently is the Falcon.
 524
 525  What you reach with this: Settings for unknown video extensions
 526aren't overridden by the driver, so you can still use the mode found
 527when booting, when the driver doesn't know to set this mode itself.
 528But this also means, that you can't switch video modes anymore...
 529
 530  An example where you may want to use "keep" is the ScreenBlaster for
 531the Falcon.
 532
 533
 5344.2) atamouse=
 535--------------
 536
 537Syntax: atamouse=<x-threshold>,[<y-threshold>]
 538
 539  With this option, you can set the mouse movement reporting threshold.
 540This is the number of pixels of mouse movement that have to accumulate
 541before the IKBD sends a new mouse packet to the kernel. Higher values
 542reduce the mouse interrupt load and thus reduce the chance of keyboard
 543overruns. Lower values give a slightly faster mouse responses and
 544slightly better mouse tracking.
 545
 546  You can set the threshold in x and y separately, but usually this is
 547of little practical use. If there's just one number in the option, it
 548is used for both dimensions. The default value is 2 for both
 549thresholds.
 550
 551
 5524.3) ataflop=
 553-------------
 554
 555Syntax: ataflop=<drive type>[,<trackbuffering>[,<steprateA>[,<steprateB>]]]
 556
 557   The drive type may be 0, 1, or 2, for DD, HD, and ED, resp. This
 558   setting affects how many buffers are reserved and which formats are
 559   probed (see also below). The default is 1 (HD). Only one drive type
 560   can be selected. If you have two disk drives, select the "better"
 561   type.
 562
 563   The second parameter <trackbuffer> tells the kernel whether to use
 564   track buffering (1) or not (0). The default is machine-dependent:
 565   no for the Medusa and yes for all others.
 566
 567   With the two following parameters, you can change the default
 568   steprate used for drive A and B, resp. 
 569
 570
 5714.4) atascsi=
 572-------------
 573
 574Syntax: atascsi=<can_queue>[,<cmd_per_lun>[,<scat-gat>[,<host-id>[,<tagged>]]]]
 575
 576  This option sets some parameters for the Atari native SCSI driver.
 577Generally, any number of arguments can be omitted from the end. And
 578for each of the numbers, a negative value means "use default". The
 579defaults depend on whether TT-style or Falcon-style SCSI is used.
 580Below, defaults are noted as n/m, where the first value refers to
 581TT-SCSI and the latter to Falcon-SCSI. If an illegal value is given
 582for one parameter, an error message is printed and that one setting is
 583ignored (others aren't affected).
 584
 585  <can_queue>:
 586    This is the maximum number of SCSI commands queued internally to the
 587    Atari SCSI driver. A value of 1 effectively turns off the driver
 588    internal multitasking (if it causes problems). Legal values are >=
 589    1. <can_queue> can be as high as you like, but values greater than
 590    <cmd_per_lun> times the number of SCSI targets (LUNs) you have
 591    don't make sense. Default: 16/8.
 592
 593  <cmd_per_lun>:
 594    Maximum number of SCSI commands issued to the driver for one
 595    logical unit (LUN, usually one SCSI target). Legal values start
 596    from 1. If tagged queuing (see below) is not used, values greater
 597    than 2 don't make sense, but waste memory. Otherwise, the maximum
 598    is the number of command tags available to the driver (currently
 599    32). Default: 8/1. (Note: Values > 1 seem to cause problems on a
 600    Falcon, cause not yet known.)
 601
 602      The <cmd_per_lun> value at a great part determines the amount of
 603    memory SCSI reserves for itself. The formula is rather
 604    complicated, but I can give you some hints:
 605      no scatter-gather  : cmd_per_lun * 232 bytes
 606      full scatter-gather: cmd_per_lun * approx. 17 Kbytes
 607
 608  <scat-gat>:
 609    Size of the scatter-gather table, i.e. the number of requests
 610    consecutive on the disk that can be merged into one SCSI command.
 611    Legal values are between 0 and 255. Default: 255/0. Note: This
 612    value is forced to 0 on a Falcon, since scatter-gather isn't
 613    possible with the ST-DMA. Not using scatter-gather hurts
 614    performance significantly.
 615
 616  <host-id>:
 617    The SCSI ID to be used by the initiator (your Atari). This is
 618    usually 7, the highest possible ID. Every ID on the SCSI bus must
 619    be unique. Default: determined at run time: If the NV-RAM checksum
 620    is valid, and bit 7 in byte 30 of the NV-RAM is set, the lower 3
 621    bits of this byte are used as the host ID. (This method is defined
 622    by Atari and also used by some TOS HD drivers.) If the above
 623    isn't given, the default ID is 7. (both, TT and Falcon).
 624
 625  <tagged>:
 626    0 means turn off tagged queuing support, all other values > 0 mean
 627    use tagged queuing for targets that support it. Default: currently
 628    off, but this may change when tagged queuing handling has been
 629    proved to be reliable.
 630
 631    Tagged queuing means that more than one command can be issued to
 632    one LUN, and the SCSI device itself orders the requests so they
 633    can be performed in optimal order. Not all SCSI devices support
 634    tagged queuing (:-().
 635
 6364.5 switches=
 637-------------
 638
 639Syntax: switches=<list of switches>
 640
 641  With this option you can switch some hardware lines that are often
 642used to enable/disable certain hardware extensions. Examples are
 643OverScan, overclocking, ...
 644
 645  The <list of switches> is a comma-separated list of the following
 646items:
 647
 648  ikbd: set RTS of the keyboard ACIA high
 649  midi: set RTS of the MIDI ACIA high
 650  snd6: set bit 6 of the PSG port A
 651  snd7: set bit 6 of the PSG port A
 652
 653It doesn't make sense to mention a switch more than once (no
 654difference to only once), but you can give as many switches as you
 655want to enable different features. The switch lines are set as early
 656as possible during kernel initialization (even before determining the
 657present hardware.)
 658
 659  All of the items can also be prefixed with "ov_", i.e. "ov_ikbd",
 660"ov_midi", ... These options are meant for switching on an OverScan
 661video extension. The difference to the bare option is that the
 662switch-on is done after video initialization, and somehow synchronized
 663to the HBLANK. A speciality is that ov_ikbd and ov_midi are switched
 664off before rebooting, so that OverScan is disabled and TOS boots
 665correctly.
 666
 667  If you give an option both, with and without the "ov_" prefix, the
 668earlier initialization ("ov_"-less) takes precedence. But the
 669switching-off on reset still happens in this case.
 670
 6715) Options for Amiga Only:
 672==========================
 673
 6745.1) video=
 675-----------
 676
 677Syntax: video=<fbname>:<sub-options...>
 678
 679The <fbname> parameter specifies the name of the frame buffer, valid
 680options are `amifb', `cyber', 'virge', `retz3' and `clgen', provided
 681that the respective frame buffer devices have been compiled into the
 682kernel (or compiled as loadable modules). The behavior of the <fbname>
 683option was changed in 2.1.57 so it is now recommended to specify this
 684option.
 685
 686The <sub-options> is a comma-separated list of the sub-options listed
 687below. This option is organized similar to the Atari version of the
 688"video"-option (4.1), but knows fewer sub-options.
 689
 6905.1.1) video mode
 691-----------------
 692
 693Again, similar to the video mode for the Atari (see 4.1.1). Predefined
 694modes depend on the used frame buffer device.
 695
 696OCS, ECS and AGA machines all use the color frame buffer. The following
 697predefined video modes are available:
 698
 699NTSC modes:
 700 - ntsc            : 640x200, 15 kHz, 60 Hz
 701 - ntsc-lace       : 640x400, 15 kHz, 60 Hz interlaced
 702PAL modes:
 703 - pal             : 640x256, 15 kHz, 50 Hz
 704 - pal-lace        : 640x512, 15 kHz, 50 Hz interlaced
 705ECS modes:
 706 - multiscan       : 640x480, 29 kHz, 57 Hz
 707 - multiscan-lace  : 640x960, 29 kHz, 57 Hz interlaced
 708 - euro36          : 640x200, 15 kHz, 72 Hz
 709 - euro36-lace     : 640x400, 15 kHz, 72 Hz interlaced
 710 - euro72          : 640x400, 29 kHz, 68 Hz
 711 - euro72-lace     : 640x800, 29 kHz, 68 Hz interlaced
 712 - super72         : 800x300, 23 kHz, 70 Hz
 713 - super72-lace    : 800x600, 23 kHz, 70 Hz interlaced
 714 - dblntsc-ff      : 640x400, 27 kHz, 57 Hz
 715 - dblntsc-lace    : 640x800, 27 kHz, 57 Hz interlaced
 716 - dblpal-ff       : 640x512, 27 kHz, 47 Hz
 717 - dblpal-lace     : 640x1024, 27 kHz, 47 Hz interlaced
 718 - dblntsc         : 640x200, 27 kHz, 57 Hz doublescan
 719 - dblpal          : 640x256, 27 kHz, 47 Hz doublescan
 720VGA modes:
 721 - vga             : 640x480, 31 kHz, 60 Hz
 722 - vga70           : 640x400, 31 kHz, 70 Hz
 723
 724Please notice that the ECS and VGA modes require either an ECS or AGA
 725chipset, and that these modes are limited to 2-bit color for the ECS
 726chipset and 8-bit color for the AGA chipset.
 727
 7285.1.2) depth
 729------------
 730
 731Syntax: depth:<nr. of bit-planes>
 732
 733Specify the number of bit-planes for the selected video-mode.
 734
 7355.1.3) inverse
 736--------------
 737
 738Use inverted display (black on white). Functionally the same as the
 739"inverse" sub-option for the Atari.
 740
 7415.1.4) font
 742-----------
 743
 744Syntax: font:<fontname>
 745
 746Specify the font to use in text modes. Functionally the same as the
 747"font" sub-option for the Atari, except that `PEARL8x8' is used instead
 748of `VGA8x8' if the vertical size of the display is less than 400 pixel
 749rows.
 750
 7515.1.5) monitorcap:
 752-------------------
 753
 754Syntax: monitorcap:<vmin>;<vmax>;<hmin>;<hmax>
 755
 756This describes the capabilities of a multisync monitor. For now, only
 757the color frame buffer uses the settings of "monitorcap:".
 758
 759  <vmin> and <vmax> are the minimum and maximum, resp., vertical frequencies
 760your monitor can work with, in Hz. <hmin> and <hmax> are the same for
 761the horizontal frequency, in kHz.
 762
 763  The defaults are 50;90;15;38 (Generic Amiga multisync monitor).
 764
 765
 7665.2) fd_def_df0=
 767----------------
 768
 769Syntax: fd_def_df0=<value>
 770
 771Sets the df0 value for "silent" floppy drives. The value should be in
 772hexadecimal with "0x" prefix.
 773
 774
 7755.3) wd33c93=
 776-------------
 777
 778Syntax: wd33c93=<sub-options...>
 779
 780These options affect the A590/A2091, A3000 and GVP Series II SCSI
 781controllers.
 782
 783The <sub-options> is a comma-separated list of the sub-options listed
 784below.
 785
 7865.3.1) nosync
 787-------------
 788
 789Syntax: nosync:bitmask
 790
 791  bitmask is a byte where the 1st 7 bits correspond with the 7
 792possible SCSI devices. Set a bit to prevent sync negotiation on that
 793device. To maintain backwards compatibility, a command-line such as
 794"wd33c93=255" will be automatically translated to
 795"wd33c93=nosync:0xff". The default is to disable sync negotiation for
 796all devices, eg. nosync:0xff.
 797
 7985.3.2) period
 799-------------
 800
 801Syntax: period:ns
 802
 803  `ns' is the minimum # of nanoseconds in a SCSI data transfer
 804period. Default is 500; acceptable values are 250 - 1000.
 805
 8065.3.3) disconnect
 807-----------------
 808
 809Syntax: disconnect:x
 810
 811  Specify x = 0 to never allow disconnects, 2 to always allow them.
 812x = 1 does 'adaptive' disconnects, which is the default and generally
 813the best choice.
 814
 8155.3.4) debug
 816------------
 817
 818Syntax: debug:x
 819
 820  If `DEBUGGING_ON' is defined, x is a bit mask that causes various
 821types of debug output to printed - see the DB_xxx defines in
 822wd33c93.h.
 823
 8245.3.5) clock
 825------------
 826
 827Syntax: clock:x
 828
 829  x = clock input in MHz for WD33c93 chip. Normal values would be from
 8308 through 20. The default value depends on your hostadapter(s),
 831default for the A3000 internal controller is 14, for the A2091 it's 8
 832and for the GVP hostadapters it's either 8 or 14, depending on the
 833hostadapter and the SCSI-clock jumper present on some GVP
 834hostadapters.
 835
 8365.3.6) next
 837-----------
 838
 839  No argument. Used to separate blocks of keywords when there's more
 840than one wd33c93-based host adapter in the system.
 841
 8425.3.7) nodma
 843------------
 844
 845Syntax: nodma:x
 846
 847  If x is 1 (or if the option is just written as "nodma"), the WD33c93
 848controller will not use DMA (= direct memory access) to access the
 849Amiga's memory.  This is useful for some systems (like A3000's and
 850A4000's with the A3640 accelerator, revision 3.0) that have problems
 851using DMA to chip memory.  The default is 0, i.e. to use DMA if
 852possible.
 853
 854
 8555.4) gvp11=
 856-----------
 857
 858Syntax: gvp11=<addr-mask>
 859
 860  The earlier versions of the GVP driver did not handle DMA
 861address-mask settings correctly which made it necessary for some
 862people to use this option, in order to get their GVP controller
 863running under Linux. These problems have hopefully been solved and the
 864use of this option is now highly unrecommended!
 865
 866  Incorrect use can lead to unpredictable behavior, so please only use
 867this option if you *know* what you are doing and have a reason to do
 868so. In any case if you experience problems and need to use this
 869option, please inform us about it by mailing to the Linux/68k kernel
 870mailing list.
 871
 872  The address mask set by this option specifies which addresses are
 873valid for DMA with the GVP Series II SCSI controller. An address is
 874valid, if no bits are set except the bits that are set in the mask,
 875too.
 876
 877  Some versions of the GVP can only DMA into a 24 bit address range,
 878some can address a 25 bit address range while others can use the whole
 87932 bit address range for DMA. The correct setting depends on your
 880controller and should be autodetected by the driver. An example is the
 88124 bit region which is specified by a mask of 0x00fffffe.
 882
 883
 884/* Local Variables: */
 885/* mode: text       */
 886/* End:             */
 887
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