2.1) root=¶

This tells the kernel which device it should mount as the rootfilesystem. The device must be a block device with a valid filesystemon it.

The first syntax gives the device by name. These names are convertedinto a major/minor number internally in the kernel in an unusual way.Normally, this “conversion” is done by the device files in /dev, butthis isn’t possible here, because the root filesystem (with /dev)isn’t mounted yet… So the kernel parses the name itself, with somehardcoded name to number mappings. The name must always be acombination 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)

The name must be followed by a decimal number, that stands for thepartition number. Internally, the value of the number is justadded to the device number mentioned in the table above. Theexceptions are /dev/ram and /dev/fd, where /dev/ram refers to aninitial ramdisk loaded by your bootstrap program (please consult theinstructions for your bootstrap program to find out how to load aninitial ramdisk). As of kernel version 2.0.18 you must specify/dev/ram as the root device if you want to boot from an initialramdisk. For the floppy devices, /dev/fd, the number stands for thefloppy drive number (there are no partitions on floppy disks). I.e.,/dev/fd0 stands for the first drive, /dev/fd1 for the second, and soon. Since the number is just added, you can also force the disk formatby adding a number greater than 3. If you look into your /devdirectory, use can see the /dev/fd0D720 has major 2 and minor 16. Youcan specify this device for the root FS by writing “root=/dev/fd16” onthe kernel command line.

[Strange and maybe uninteresting stuff ON]

This unusual translation of device names has some strangeconsequences: If, for example, you have a symbolic link from /dev/fdto /dev/fd0D720 as an abbreviation for floppy driver #0 in DD format,you cannot use this name for specifying the root device, because thekernel cannot see this symlink before mounting the root FS and itisn’t in the table above. If you use it, the root device will not beset at all, without an error message. Another example: You cannot use apartition on e.g. the sixth SCSI disk as the root filesystem, if youwant 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 canuse the sixth SCSI disk for the root FS, but you have to specify thedevice by number… (see below). Or, even more strange, you can use thefact that there is no range checking of the partition number, and yourknowledge 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 tableabove, you can also specify it by major and minor numbers. These arewritten in hex, with no prefix and no separator between. E.g., if youhave a CD with contents appropriate as a root filesystem in the firstSCSI 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 forthe first of these. You can find out all valid major numbers bylooking into include/linux/major.h.

In addition to major and minor numbers, if the device containing yourroot partition uses a partition table format with unique partitionidentifiers, then you may use them. For instance,“root=PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF”. It is alsopossible to reference another partition on the same device using aknown partition UUID as the starting point. For example,if partition 5 of the device has the UUID of00112233-4455-6677-8899-AABBCCDDEEFF then partition 3 may be found asfollows:

PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF/PARTNROFF=-2

Authoritative information can be found in“Documentation/admin-guide/kernel-parameters.rst”.

2.2) ro, rw¶

These two options tell the kernel whether it should mount the rootfilesystem read-only or read-write. The default is read-only, exceptfor ramdisks, which default to read-write.

2.3) debug¶

This raises the kernel log level to 10 (the default is 7). This is thesame level as set by the “dmesg” command, just that the maximum levelselectable by dmesg is 8.

2.4) debug=¶

This option causes certain kernel messages be printed to the selecteddebugging device. This can aid debugging the kernel, since themessages can be captured and analyzed on some other machine. Whichdevices are possible depends on the machine type. There are no checksfor the validity of the device name. If the device isn’t implemented,nothing happens.

Messages logged this way are in general stack dumps after kernelmemory faults or bad kernel traps, and kernel panics. To be exact: allmessages of level 0 (panic messages) and all messages printed whilethe log level is 8 or more (their level doesn’t matter). Before stackdumps, the kernel sets the log level to 10 automatically. A level ofat least 8 can also be set by the “debug” command line option (see2.3) 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. Afterrebooting, 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 portThis 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 thecase there’s no printer connected (else the kernel wouldlock up). The timeout is not exact, but usually a fewseconds.

2.6) ramdisk_size=¶

This option instructs the kernel to set up a ramdisk of the givensize in KBytes. Do not use this option if the ramdisk contents arepassed by bootstrap! In this case, the size is selected automaticallyand should not be overwritten.

The only application is for root filesystems on floppy disks, thatshould be loaded into memory. To do that, select the correspondingsize of the disk as ramdisk size, and set the root device to the diskdrive (with “root=”).

2.7) swap=

I can’t find any sign of this option in 2.2.6.

2.8) buff=¶

I can’t find any sign of this option in 2.2.6.

3.1) ether=¶

<dev-name> is the name of a net driver, as specified indrivers/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 thesettings by this options. Also, the existing ethernet drivers forLinux/m68k (ariadne, a2065, hydra) don’t use them because Zorro boardsare really Plug-‘n-Play, so the “ether=” option is useless altogetherfor Linux/m68k.

3.2) 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 haveto use this option, since the kernel can obtain the geometry dataitself. It exists just for the case that this fails for one of yourdisks.

3.3) max_scsi_luns=¶

Sets the maximum number of LUNs (logical units) of SCSI devices tobe scanned. Valid values for <n> are between 1 and 8. Default is 8 if“Probe all LUNs on each SCSI device” was selected during the kernelconfiguration, else 1.

3.4) st=¶

Sets several parameters of the SCSI tape driver. <buffer_size> isthe number of 512-byte buffers reserved for tape operations for eachdevice. <write_thres> sets the number of blocks which must be filledto start an actual write operation to the tape. Maximum value is thetotal number of buffers. <max_buffer> limits the total number ofbuffers allocated for all tape devices.

3.5) dmasound=¶

This option controls some configurations of the Linux/m68k DMA sounddriver (Amiga and Atari): <buffers> is the number of buffers you wantto use (minimum 4, default 4), <buffer-size> is the size of eachbuffer in kilobytes (minimum 4, default 32) and <catch-radius> sayshow much percent of error will be tolerated when setting a frequency(maximum 10, default 0). For example with 3% you can play 8000HzAU-Files on the Falcon with its hardware frequency of 8195Hz and thusdon’t need to expand the sound.

4.1) video=¶

The <fbname> parameter specifies the name of the frame buffer,eg. most atari users will want to specifyatafb here. The<sub-options> is a comma-separated list of the sub-options listedbelow.

NB:

Please notice that this option was renamed fromatavideo tovideo during the development of the 1.3.x kernels, thus youmight need to update your boot-scripts if upgrading to 2.x froman 1.2.x kernel.

NBB:

The behavior of video= was changed in 2.1.57 so the recommendedoption 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 listedin atari/atafb.c in the Linux/m68k source tree. The kernel willactivate the given video mode at boot time and make it the defaultmode, 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 themodes names “default<n>” in turn, until one is possible with thehardware in use.

A video mode setting doesn’t make sense, if the external driver isactivated 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 thisoption, you can make the background white.

4.1.3) font¶

Specify the font to use in text modes. Currently you can choose onlybetweenVGA8x8,VGA8x16 andPEARL8x8.VGA8x8 is default, if thevertical size of the display is less than 400 pixel rows. Otherwise, theVGA8x16 font is the default.

4.1.4)hwscroll_¶

The number of additional lines of video memory to reserve forspeeding up the scrolling (“hardware scrolling”). Hardware scrollingis possible only if the kernel can set the video base address in stepsfine enough. This is true for STE, MegaSTE, TT, and Falcon. It is notpossible with plain STs and graphics cards (The former because thebase address must be on a 256 byte boundary there, the latter becausethe kernel doesn’t know how to set the base address at all.)

By default, <n> is set to the number of visible text lines on thedisplay. Thus, the amount of video memory is doubled, compared to nohardware scrolling. You can turn off the hardware scrolling altogetherby setting <n> to 0.

4.1.5) internal:¶

This option specifies the capabilities of some extended internal videohardware, like e.g. OverScan. <xres> and <yres> give the (extended)dimensions of the screen.

If your OverScan needs a black border, you have to write the lastthree arguments of the “internal:”. <xres_max> is the maximum linelength the hardware allows, <yres_max> the maximum number of lines.<offset> is the offset of the visible part of the screen memory to itsphysical start, in bytes.

Often, extended interval video hardware has to be activated somehow.For this, see the “sw_*” options below.

4.1.6) external:¶

This is probably the most complicated parameter… It specifies thatyou have some external video hardware (a graphics board), and how touse it under Linux/m68k. The kernel cannot know more about the hardwarethan you tell it here! The kernel also is unable to set or change anyvideo modes, since it doesn’t know about any board internal. So, youhave to switch to that video mode before you start Linux, and cannotswitch to another mode once Linux has started.

The first 3 parameters of this sub-option should be obvious: <xres>,<yres> and <depth> give the dimensions of the screen and the number ofplanes (depth). The depth is the logarithm to base 2 of the numberof colors possible. (Or, the other way round: The number of colors is2^depth).

You have to tell the kernel furthermore how the video memory isorganized. This is done by a letter as <org> parameter:

‘n’:

“normal planes”, i.e. one whole plane after another

‘i’:

“interleaved planes”, i.e. 16 bit of the first plane, than 16 bitof the next, and so on… This mode is used only with thebuilt-in Atari video modes, I think there is no card thatsupports this mode.

‘p’:

“packed pixels”, i.e. <depth> consecutive bits stand for allplanes 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 colorlookup table); usually depth is 24

For monochrome modes (i.e., <depth> is 1), the <org> letter has adifferent 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 baseaddress of the video memory. That is given in the <scrmem> parameter,as a hexadecimal number with a “0x” prefix. You have to find out thisaddress in the documentation of your hardware.

The next parameter, <scrlen>, tells the kernel about the size of thevideo memory. If it’s missing, the size is calculated from <xres>,<yres>, and <depth>. For now, it is not useful to write a value here.It would be used only for hardware scrolling (which isn’t possiblewith the external driver, because the kernel cannot set the video baseaddress), or for virtual resolutions under X (which the X serverdoesn’t support yet). So, it’s currently best to leave this fieldempty, either by ending the “external:” after the video address or bywriting two consecutive semicolons, if you want to give a <vgabase>(it is allowed to leave this parameter empty).

The <vgabase> parameter is optional. If it is not given, the kernelcannot read or write any color registers of the video hardware, andthus you have to set appropriate colors before you start Linux. But ifyour card is somehow VGA compatible, you can tell the kernel the baseaddress of the VGA register set, so it can change the color lookuptable. You have to look up this address in your board’s documentation.To avoid misunderstandings: <vgabase> is the _base_ address, i.e. a 4kaligned address. For read/writing the color registers, the kerneluses the addresses vgabase+0x3c7…vgabase+0x3c9. The <vgabase>parameter is written in hexadecimal with a “0x” prefix, just as<scrmem>.

<colw> is meaningful only if <vgabase> is specified. It tells thekernel how wide each of the color register is, i.e. the number of bitsper single color (red/green/blue). Default is 6, another quite usualvalue is 8.

Also <coltype> is used together with <vgabase>. It tells the kernelabout the color register model of your gfx board. Currently, the types“vga” (which is also the default) and “mv300” (SANG MV300) areimplemented.

Parameter <xres_virtual> is required for ProMST or ET4000 cards wherethe physical linelength differs from the visible length. With ProMST,xres_virtual must be set to 2048. For ET4000, xres_virtual depends on theinitialisation 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. Thiscurrently works only with the ScreenWonder!

4.1.8) monitorcap:¶

This describes the capabilities of a multisync monitor. Don’t use itwith a fixed-frequency monitor! For now, only the Falcon frame bufferuses the settings of “monitorcap:”.

<vmin> and <vmax> are the minimum and maximum, resp., vertical frequenciesyour monitor can work with, in Hz. <hmin> and <hmax> are the same forthe 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 videomode calculations and settings on its own. The only Atari fb devicethat does this currently is the Falcon.

What you reach with this: Settings for unknown video extensionsaren’t overridden by the driver, so you can still use the mode foundwhen 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 forthe Falcon.

4.2) atamouse=¶

With this option, you can set the mouse movement reporting threshold.This is the number of pixels of mouse movement that have to accumulatebefore the IKBD sends a new mouse packet to the kernel. Higher valuesreduce the mouse interrupt load and thus reduce the chance of keyboardoverruns. Lower values give a slightly faster mouse responses andslightly better mouse tracking.

You can set the threshold in x and y separately, but usually this isof little practical use. If there’s just one number in the option, itis used for both dimensions. The default value is 2 for boththresholds.

4.3) ataflop=¶

4.4) atascsi=¶

This option sets some parameters for the Atari native SCSI driver.Generally, any number of arguments can be omitted from the end. Andfor each of the numbers, a negative value means “use default”. Thedefaults depend on whether TT-style or Falcon-style SCSI is used.Below, defaults are noted as n/m, where the first value refers toTT-SCSI and the latter to Falcon-SCSI. If an illegal value is givenfor one parameter, an error message is printed and that one setting isignored (others aren’t affected).

<can_queue>:

This is the maximum number of SCSI commands queued internally to theAtari SCSI driver. A value of 1 effectively turns off the driverinternal multitasking (if it causes problems). Legal values are >=1. <can_queue> can be as high as you like, but values greater than<cmd_per_lun> times the number of SCSI targets (LUNs) you havedon’t make sense. Default: 16/8.

<cmd_per_lun>:

Maximum number of SCSI commands issued to the driver for onelogical unit (LUN, usually one SCSI target). Legal values startfrom 1. If tagged queuing (see below) is not used, values greaterthan 2 don’t make sense, but waste memory. Otherwise, the maximumis the number of command tags available to the driver (currently32). Default: 8/1. (Note: Values > 1 seem to cause problems on aFalcon, cause not yet known.)

The <cmd_per_lun> value at a great part determines the amount ofmemory SCSI reserves for itself. The formula is rathercomplicated, but I can give you some hints:

no scatter-gather:

cmd_per_lun * 232 bytes

full scatter-gather:

cmd_per_lun * approx. 17 Kbytes

<scat-gat>:

Size of the scatter-gather table, i.e. the number of requestsconsecutive on the disk that can be merged into one SCSI command.Legal values are between 0 and 255. Default: 255/0. Note: Thisvalue is forced to 0 on a Falcon, since scatter-gather isn’tpossible with the ST-DMA. Not using scatter-gather hurtsperformance significantly.

<host-id>:

The SCSI ID to be used by the initiator (your Atari). This isusually 7, the highest possible ID. Every ID on the SCSI bus mustbe unique. Default: determined at run time: If the NV-RAM checksumis valid, and bit 7 in byte 30 of the NV-RAM is set, the lower 3bits of this byte are used as the host ID. (This method is definedby Atari and also used by some TOS HD drivers.) If the aboveisn’t given, the default ID is 7. (both, TT and Falcon).

<tagged>:

0 means turn off tagged queuing support, all other values > 0 meanuse tagged queuing for targets that support it. Default: currentlyoff, but this may change when tagged queuing handling has beenproved to be reliable.

Tagged queuing means that more than one command can be issued toone LUN, and the SCSI device itself orders the requests so theycan be performed in optimal order. Not all SCSI devices supporttagged queuing (:-().

4.5 switches=¶

With this option you can switch some hardware lines that are oftenused to enable/disable certain hardware extensions. Examples areOverScan, overclocking, …

The <list of switches> is a comma-separated list of the followingitems:

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 (nodifference to only once), but you can give as many switches as youwant to enable different features. The switch lines are set as earlyas possible during kernel initialization (even before determining thepresent hardware.)

All of the items can also be prefixed withov_, i.e.ov_ikbd,ov_midi, … These options are meant for switching on an OverScanvideo extension. The difference to the bare option is that theswitch-on is done after video initialization, and somehow synchronizedto the HBLANK. A speciality is that ov_ikbd and ov_midi are switchedoff before rebooting, so that OverScan is disabled and TOS bootscorrectly.

If you give an option both, with and without theov_ prefix, theearlier initialization (ov_-less) takes precedence. But theswitching-off on reset still happens in this case.

5.1) video=¶

The <fbname> parameter specifies the name of the frame buffer, validoptions areamifb,cyber, ‘virge’,retz3 andclgen, providedthat the respective frame buffer devices have been compiled into thekernel (or compiled as loadable modules). The behavior of the <fbname>option was changed in 2.1.57 so it is now recommended to specify thisoption.

The <sub-options> is a comma-separated list of the sub-options listedbelow. 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). Predefinedmodes depend on the used frame buffer device.

OCS, ECS and AGA machines all use the color frame buffer. The followingpredefined 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 AGAchipset, and that these modes are limited to 2-bit color for the ECSchipset and 8-bit color for the AGA chipset.

5.1.2) 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¶

Specify the font to use in text modes. Functionally the same as the“font” sub-option for the Atari, except thatPEARL8x8 is used insteadofVGA8x8 if the vertical size of the display is less than 400 pixelrows.

5.1.5) monitorcap:¶

This describes the capabilities of a multisync monitor. For now, onlythe color frame buffer uses the settings of “monitorcap:”.

<vmin> and <vmax> are the minimum and maximum, resp., vertical frequenciesyour monitor can work with, in Hz. <hmin> and <hmax> are the same forthe horizontal frequency, in kHz.

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

5.2) fd_def_df0=¶

Sets the df0 value for “silent” floppy drives. The value should be inhexadecimal with “0x” prefix.

5.3) wd33c93=¶

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

The <sub-options> is a comma-separated list of the sub-options listedbelow.

5.3.1) nosync¶

bitmask is a byte where the 1st 7 bits correspond with the 7possible SCSI devices. Set a bit to prevent sync negotiation on thatdevice. 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 forall devices, eg. nosync:0xff.

5.3.2) period¶

ns is the minimum # of nanoseconds in a SCSI data transferperiod. Default is 500; acceptable values are 250 - 1000.

5.3.3) disconnect¶

Specify x = 0 to never allow disconnects, 2 to always allow them.x = 1 does ‘adaptive’ disconnects, which is the default and generallythe best choice.

5.3.4) debug¶

IfDEBUGGING_ON is defined, x is a bit mask that causes varioustypes of debug output to printed - see the DB_xxx defines inwd33c93.h.

5.3.5) clock¶

x = clock input in MHz for WD33c93 chip. Normal values would be from8 through 20. The default value depends on your hostadapter(s),default for the A3000 internal controller is 14, for the A2091 it’s 8and for the GVP hostadapters it’s either 8 or 14, depending on thehostadapter and the SCSI-clock jumper present on some GVPhostadapters.

5.3.6) next¶

No argument. Used to separate blocks of keywords when there’s morethan one wd33c93-based host adapter in the system.

5.3.7) nodma¶

If x is 1 (or if the option is just written as “nodma”), the WD33c93controller will not use DMA (= direct memory access) to access theAmiga’s memory. This is useful for some systems (like A3000’s andA4000’s with the A3640 accelerator, revision 3.0) that have problemsusing DMA to chip memory. The default is 0, i.e. to use DMA ifpossible.

5.4) gvp11=¶

The earlier versions of the GVP driver did not handle DMAaddress-mask settings correctly which made it necessary for somepeople to use this option, in order to get their GVP controllerrunning under Linux. These problems have hopefully been solved and theuse of this option is now highly unrecommended!

Incorrect use can lead to unpredictable behavior, so please only usethis option if youknow what you are doing and have a reason to doso. In any case if you experience problems and need to use thisoption, please inform us about it by mailing to the Linux/68k kernelmailing list.

The address mask set by this option specifies which addresses arevalid for DMA with the GVP Series II SCSI controller. An address isvalid, 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 whole32 bit address range for DMA. The correct setting depends on yourcontroller and should be autodetected by the driver. An example is the24 bit region which is specified by a mask of 0x00fffffe.