kernel-options.rst 32 KB

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  1. ===================================
  2. Command Line Options for Linux/m68k
  3. ===================================
  4. Last Update: 2 May 1999
  5. Linux/m68k version: 2.2.6
  6. Author: Roman.Hodek@informatik.uni-erlangen.de (Roman Hodek)
  7. Update: jds@kom.auc.dk (Jes Sorensen) and faq@linux-m68k.org (Chris Lawrence)
  8. 0) Introduction
  9. ===============
  10. Often I've been asked which command line options the Linux/m68k
  11. kernel understands, or how the exact syntax for the ... option is, or
  12. ... about the option ... . I hope, this document supplies all the
  13. answers...
  14. Note that some options might be outdated, their descriptions being
  15. incomplete or missing. Please update the information and send in the
  16. patches.
  17. 1) Overview of the Kernel's Option Processing
  18. =============================================
  19. The kernel knows three kinds of options on its command line:
  20. 1) kernel options
  21. 2) environment settings
  22. 3) arguments for init
  23. To which of these classes an argument belongs is determined as
  24. follows: If the option is known to the kernel itself, i.e. if the name
  25. (the part before the '=') or, in some cases, the whole argument string
  26. is known to the kernel, it belongs to class 1. Otherwise, if the
  27. argument contains an '=', it is of class 2, and the definition is put
  28. into init's environment. All other arguments are passed to init as
  29. command line options.
  30. This document describes the valid kernel options for Linux/m68k in
  31. the version mentioned at the start of this file. Later revisions may
  32. add new such options, and some may be missing in older versions.
  33. In general, the value (the part after the '=') of an option is a
  34. list of values separated by commas. The interpretation of these values
  35. is up to the driver that "owns" the option. This association of
  36. options with drivers is also the reason that some are further
  37. subdivided.
  38. 2) General Kernel Options
  39. =========================
  40. 2.1) root=
  41. ----------
  42. :Syntax: root=/dev/<device>
  43. :or: root=<hex_number>
  44. This tells the kernel which device it should mount as the root
  45. filesystem. The device must be a block device with a valid filesystem
  46. on it.
  47. The first syntax gives the device by name. These names are converted
  48. into a major/minor number internally in the kernel in an unusual way.
  49. Normally, this "conversion" is done by the device files in /dev, but
  50. this isn't possible here, because the root filesystem (with /dev)
  51. isn't mounted yet... So the kernel parses the name itself, with some
  52. hardcoded name to number mappings. The name must always be a
  53. combination of two or three letters, followed by a decimal number.
  54. Valid names are::
  55. /dev/ram: -> 0x0100 (initial ramdisk)
  56. /dev/hda: -> 0x0300 (first IDE disk)
  57. /dev/hdb: -> 0x0340 (second IDE disk)
  58. /dev/sda: -> 0x0800 (first SCSI disk)
  59. /dev/sdb: -> 0x0810 (second SCSI disk)
  60. /dev/sdc: -> 0x0820 (third SCSI disk)
  61. /dev/sdd: -> 0x0830 (forth SCSI disk)
  62. /dev/sde: -> 0x0840 (fifth SCSI disk)
  63. /dev/fd : -> 0x0200 (floppy disk)
  64. The name must be followed by a decimal number, that stands for the
  65. partition number. Internally, the value of the number is just
  66. added to the device number mentioned in the table above. The
  67. exceptions are /dev/ram and /dev/fd, where /dev/ram refers to an
  68. initial ramdisk loaded by your bootstrap program (please consult the
  69. instructions for your bootstrap program to find out how to load an
  70. initial ramdisk). As of kernel version 2.0.18 you must specify
  71. /dev/ram as the root device if you want to boot from an initial
  72. ramdisk. For the floppy devices, /dev/fd, the number stands for the
  73. floppy drive number (there are no partitions on floppy disks). I.e.,
  74. /dev/fd0 stands for the first drive, /dev/fd1 for the second, and so
  75. on. Since the number is just added, you can also force the disk format
  76. by adding a number greater than 3. If you look into your /dev
  77. directory, use can see the /dev/fd0D720 has major 2 and minor 16. You
  78. can specify this device for the root FS by writing "root=/dev/fd16" on
  79. the kernel command line.
  80. [Strange and maybe uninteresting stuff ON]
  81. This unusual translation of device names has some strange
  82. consequences: If, for example, you have a symbolic link from /dev/fd
  83. to /dev/fd0D720 as an abbreviation for floppy driver #0 in DD format,
  84. you cannot use this name for specifying the root device, because the
  85. kernel cannot see this symlink before mounting the root FS and it
  86. isn't in the table above. If you use it, the root device will not be
  87. set at all, without an error message. Another example: You cannot use a
  88. partition on e.g. the sixth SCSI disk as the root filesystem, if you
  89. want to specify it by name. This is, because only the devices up to
  90. /dev/sde are in the table above, but not /dev/sdf. Although, you can
  91. use the sixth SCSI disk for the root FS, but you have to specify the
  92. device by number... (see below). Or, even more strange, you can use the
  93. fact that there is no range checking of the partition number, and your
  94. knowledge that each disk uses 16 minors, and write "root=/dev/sde17"
  95. (for /dev/sdf1).
  96. [Strange and maybe uninteresting stuff OFF]
  97. If the device containing your root partition isn't in the table
  98. above, you can also specify it by major and minor numbers. These are
  99. written in hex, with no prefix and no separator between. E.g., if you
  100. have a CD with contents appropriate as a root filesystem in the first
  101. SCSI CD-ROM drive, you boot from it by "root=0b00". Here, hex "0b" =
  102. decimal 11 is the major of SCSI CD-ROMs, and the minor 0 stands for
  103. the first of these. You can find out all valid major numbers by
  104. looking into include/linux/major.h.
  105. In addition to major and minor numbers, if the device containing your
  106. root partition uses a partition table format with unique partition
  107. identifiers, then you may use them. For instance,
  108. "root=PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF". It is also
  109. possible to reference another partition on the same device using a
  110. known partition UUID as the starting point. For example,
  111. if partition 5 of the device has the UUID of
  112. 00112233-4455-6677-8899-AABBCCDDEEFF then partition 3 may be found as
  113. follows:
  114. PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF/PARTNROFF=-2
  115. Authoritative information can be found in
  116. "Documentation/admin-guide/kernel-parameters.rst".
  117. 2.2) ro, rw
  118. -----------
  119. :Syntax: ro
  120. :or: rw
  121. These two options tell the kernel whether it should mount the root
  122. filesystem read-only or read-write. The default is read-only, except
  123. for ramdisks, which default to read-write.
  124. 2.3) debug
  125. ----------
  126. :Syntax: debug
  127. This raises the kernel log level to 10 (the default is 7). This is the
  128. same level as set by the "dmesg" command, just that the maximum level
  129. selectable by dmesg is 8.
  130. 2.4) debug=
  131. -----------
  132. :Syntax: debug=<device>
  133. This option causes certain kernel messages be printed to the selected
  134. debugging device. This can aid debugging the kernel, since the
  135. messages can be captured and analyzed on some other machine. Which
  136. devices are possible depends on the machine type. There are no checks
  137. for the validity of the device name. If the device isn't implemented,
  138. nothing happens.
  139. Messages logged this way are in general stack dumps after kernel
  140. memory faults or bad kernel traps, and kernel panics. To be exact: all
  141. messages of level 0 (panic messages) and all messages printed while
  142. the log level is 8 or more (their level doesn't matter). Before stack
  143. dumps, the kernel sets the log level to 10 automatically. A level of
  144. at least 8 can also be set by the "debug" command line option (see
  145. 2.3) and at run time with "dmesg -n 8".
  146. Devices possible for Amiga:
  147. - "ser":
  148. built-in serial port; parameters: 9600bps, 8N1
  149. - "mem":
  150. Save the messages to a reserved area in chip mem. After
  151. rebooting, they can be read under AmigaOS with the tool
  152. 'dmesg'.
  153. Devices possible for Atari:
  154. - "ser1":
  155. ST-MFP serial port ("Modem1"); parameters: 9600bps, 8N1
  156. - "ser2":
  157. SCC channel B serial port ("Modem2"); parameters: 9600bps, 8N1
  158. - "ser" :
  159. default serial port
  160. This is "ser2" for a Falcon, and "ser1" for any other machine
  161. - "midi":
  162. The MIDI port; parameters: 31250bps, 8N1
  163. - "par" :
  164. parallel port
  165. The printing routine for this implements a timeout for the
  166. case there's no printer connected (else the kernel would
  167. lock up). The timeout is not exact, but usually a few
  168. seconds.
  169. 2.6) ramdisk_size=
  170. ------------------
  171. :Syntax: ramdisk_size=<size>
  172. This option instructs the kernel to set up a ramdisk of the given
  173. size in KBytes. Do not use this option if the ramdisk contents are
  174. passed by bootstrap! In this case, the size is selected automatically
  175. and should not be overwritten.
  176. The only application is for root filesystems on floppy disks, that
  177. should be loaded into memory. To do that, select the corresponding
  178. size of the disk as ramdisk size, and set the root device to the disk
  179. drive (with "root=").
  180. 2.7) swap=
  181. I can't find any sign of this option in 2.2.6.
  182. 2.8) buff=
  183. -----------
  184. I can't find any sign of this option in 2.2.6.
  185. 3) General Device Options (Amiga and Atari)
  186. ===========================================
  187. 3.1) ether=
  188. -----------
  189. :Syntax: ether=[<irq>[,<base_addr>[,<mem_start>[,<mem_end>]]]],<dev-name>
  190. <dev-name> is the name of a net driver, as specified in
  191. drivers/net/Space.c in the Linux source. Most prominent are eth0, ...
  192. eth3, sl0, ... sl3, ppp0, ..., ppp3, dummy, and lo.
  193. The non-ethernet drivers (sl, ppp, dummy, lo) obviously ignore the
  194. settings by this options. Also, the existing ethernet drivers for
  195. Linux/m68k (ariadne, a2065, hydra) don't use them because Zorro boards
  196. are really Plug-'n-Play, so the "ether=" option is useless altogether
  197. for Linux/m68k.
  198. 3.2) hd=
  199. --------
  200. :Syntax: hd=<cylinders>,<heads>,<sectors>
  201. This option sets the disk geometry of an IDE disk. The first hd=
  202. option is for the first IDE disk, the second for the second one.
  203. (I.e., you can give this option twice.) In most cases, you won't have
  204. to use this option, since the kernel can obtain the geometry data
  205. itself. It exists just for the case that this fails for one of your
  206. disks.
  207. 3.3) max_scsi_luns=
  208. -------------------
  209. :Syntax: max_scsi_luns=<n>
  210. Sets the maximum number of LUNs (logical units) of SCSI devices to
  211. be scanned. Valid values for <n> are between 1 and 8. Default is 8 if
  212. "Probe all LUNs on each SCSI device" was selected during the kernel
  213. configuration, else 1.
  214. 3.4) st=
  215. --------
  216. :Syntax: st=<buffer_size>,[<write_thres>,[<max_buffers>]]
  217. Sets several parameters of the SCSI tape driver. <buffer_size> is
  218. the number of 512-byte buffers reserved for tape operations for each
  219. device. <write_thres> sets the number of blocks which must be filled
  220. to start an actual write operation to the tape. Maximum value is the
  221. total number of buffers. <max_buffer> limits the total number of
  222. buffers allocated for all tape devices.
  223. 3.5) dmasound=
  224. --------------
  225. :Syntax: dmasound=[<buffers>,<buffer-size>[,<catch-radius>]]
  226. This option controls some configurations of the Linux/m68k DMA sound
  227. driver (Amiga and Atari): <buffers> is the number of buffers you want
  228. to use (minimum 4, default 4), <buffer-size> is the size of each
  229. buffer in kilobytes (minimum 4, default 32) and <catch-radius> says
  230. how much percent of error will be tolerated when setting a frequency
  231. (maximum 10, default 0). For example with 3% you can play 8000Hz
  232. AU-Files on the Falcon with its hardware frequency of 8195Hz and thus
  233. don't need to expand the sound.
  234. 4) Options for Atari Only
  235. =========================
  236. 4.1) video=
  237. -----------
  238. :Syntax: video=<fbname>:<sub-options...>
  239. The <fbname> parameter specifies the name of the frame buffer,
  240. eg. most atari users will want to specify `atafb` here. The
  241. <sub-options> is a comma-separated list of the sub-options listed
  242. below.
  243. NB:
  244. Please notice that this option was renamed from `atavideo` to
  245. `video` during the development of the 1.3.x kernels, thus you
  246. might need to update your boot-scripts if upgrading to 2.x from
  247. an 1.2.x kernel.
  248. NBB:
  249. The behavior of video= was changed in 2.1.57 so the recommended
  250. option is to specify the name of the frame buffer.
  251. 4.1.1) Video Mode
  252. -----------------
  253. This sub-option may be any of the predefined video modes, as listed
  254. in atari/atafb.c in the Linux/m68k source tree. The kernel will
  255. activate the given video mode at boot time and make it the default
  256. mode, if the hardware allows. Currently defined names are:
  257. - stlow : 320x200x4
  258. - stmid, default5 : 640x200x2
  259. - sthigh, default4: 640x400x1
  260. - ttlow : 320x480x8, TT only
  261. - ttmid, default1 : 640x480x4, TT only
  262. - tthigh, default2: 1280x960x1, TT only
  263. - vga2 : 640x480x1, Falcon only
  264. - vga4 : 640x480x2, Falcon only
  265. - vga16, default3 : 640x480x4, Falcon only
  266. - vga256 : 640x480x8, Falcon only
  267. - falh2 : 896x608x1, Falcon only
  268. - falh16 : 896x608x4, Falcon only
  269. If no video mode is given on the command line, the kernel tries the
  270. modes names "default<n>" in turn, until one is possible with the
  271. hardware in use.
  272. A video mode setting doesn't make sense, if the external driver is
  273. activated by a "external:" sub-option.
  274. 4.1.2) inverse
  275. --------------
  276. Invert the display. This affects both, text (consoles) and graphics
  277. (X) display. Usually, the background is chosen to be black. With this
  278. option, you can make the background white.
  279. 4.1.3) font
  280. -----------
  281. :Syntax: font:<fontname>
  282. Specify the font to use in text modes. Currently you can choose only
  283. between `VGA8x8`, `VGA8x16` and `PEARL8x8`. `VGA8x8` is default, if the
  284. vertical size of the display is less than 400 pixel rows. Otherwise, the
  285. `VGA8x16` font is the default.
  286. 4.1.4) `hwscroll_`
  287. ------------------
  288. :Syntax: `hwscroll_<n>`
  289. The number of additional lines of video memory to reserve for
  290. speeding up the scrolling ("hardware scrolling"). Hardware scrolling
  291. is possible only if the kernel can set the video base address in steps
  292. fine enough. This is true for STE, MegaSTE, TT, and Falcon. It is not
  293. possible with plain STs and graphics cards (The former because the
  294. base address must be on a 256 byte boundary there, the latter because
  295. the kernel doesn't know how to set the base address at all.)
  296. By default, <n> is set to the number of visible text lines on the
  297. display. Thus, the amount of video memory is doubled, compared to no
  298. hardware scrolling. You can turn off the hardware scrolling altogether
  299. by setting <n> to 0.
  300. 4.1.5) internal:
  301. ----------------
  302. :Syntax: internal:<xres>;<yres>[;<xres_max>;<yres_max>;<offset>]
  303. This option specifies the capabilities of some extended internal video
  304. hardware, like e.g. OverScan. <xres> and <yres> give the (extended)
  305. dimensions of the screen.
  306. If your OverScan needs a black border, you have to write the last
  307. three arguments of the "internal:". <xres_max> is the maximum line
  308. length the hardware allows, <yres_max> the maximum number of lines.
  309. <offset> is the offset of the visible part of the screen memory to its
  310. physical start, in bytes.
  311. Often, extended interval video hardware has to be activated somehow.
  312. For this, see the "sw_*" options below.
  313. 4.1.6) external:
  314. ----------------
  315. :Syntax:
  316. external:<xres>;<yres>;<depth>;<org>;<scrmem>[;<scrlen>[;<vgabase>
  317. [;<colw>[;<coltype>[;<xres_virtual>]]]]]
  318. .. I had to break this line...
  319. This is probably the most complicated parameter... It specifies that
  320. you have some external video hardware (a graphics board), and how to
  321. use it under Linux/m68k. The kernel cannot know more about the hardware
  322. than you tell it here! The kernel also is unable to set or change any
  323. video modes, since it doesn't know about any board internal. So, you
  324. have to switch to that video mode before you start Linux, and cannot
  325. switch to another mode once Linux has started.
  326. The first 3 parameters of this sub-option should be obvious: <xres>,
  327. <yres> and <depth> give the dimensions of the screen and the number of
  328. planes (depth). The depth is the logarithm to base 2 of the number
  329. of colors possible. (Or, the other way round: The number of colors is
  330. 2^depth).
  331. You have to tell the kernel furthermore how the video memory is
  332. organized. This is done by a letter as <org> parameter:
  333. 'n':
  334. "normal planes", i.e. one whole plane after another
  335. 'i':
  336. "interleaved planes", i.e. 16 bit of the first plane, than 16 bit
  337. of the next, and so on... This mode is used only with the
  338. built-in Atari video modes, I think there is no card that
  339. supports this mode.
  340. 'p':
  341. "packed pixels", i.e. <depth> consecutive bits stand for all
  342. planes of one pixel; this is the most common mode for 8 planes
  343. (256 colors) on graphic cards
  344. 't':
  345. "true color" (more or less packed pixels, but without a color
  346. lookup table); usually depth is 24
  347. For monochrome modes (i.e., <depth> is 1), the <org> letter has a
  348. different meaning:
  349. 'n':
  350. normal colors, i.e. 0=white, 1=black
  351. 'i':
  352. inverted colors, i.e. 0=black, 1=white
  353. The next important information about the video hardware is the base
  354. address of the video memory. That is given in the <scrmem> parameter,
  355. as a hexadecimal number with a "0x" prefix. You have to find out this
  356. address in the documentation of your hardware.
  357. The next parameter, <scrlen>, tells the kernel about the size of the
  358. video memory. If it's missing, the size is calculated from <xres>,
  359. <yres>, and <depth>. For now, it is not useful to write a value here.
  360. It would be used only for hardware scrolling (which isn't possible
  361. with the external driver, because the kernel cannot set the video base
  362. address), or for virtual resolutions under X (which the X server
  363. doesn't support yet). So, it's currently best to leave this field
  364. empty, either by ending the "external:" after the video address or by
  365. writing two consecutive semicolons, if you want to give a <vgabase>
  366. (it is allowed to leave this parameter empty).
  367. The <vgabase> parameter is optional. If it is not given, the kernel
  368. cannot read or write any color registers of the video hardware, and
  369. thus you have to set appropriate colors before you start Linux. But if
  370. your card is somehow VGA compatible, you can tell the kernel the base
  371. address of the VGA register set, so it can change the color lookup
  372. table. You have to look up this address in your board's documentation.
  373. To avoid misunderstandings: <vgabase> is the _base_ address, i.e. a 4k
  374. aligned address. For read/writing the color registers, the kernel
  375. uses the addresses vgabase+0x3c7...vgabase+0x3c9. The <vgabase>
  376. parameter is written in hexadecimal with a "0x" prefix, just as
  377. <scrmem>.
  378. <colw> is meaningful only if <vgabase> is specified. It tells the
  379. kernel how wide each of the color register is, i.e. the number of bits
  380. per single color (red/green/blue). Default is 6, another quite usual
  381. value is 8.
  382. Also <coltype> is used together with <vgabase>. It tells the kernel
  383. about the color register model of your gfx board. Currently, the types
  384. "vga" (which is also the default) and "mv300" (SANG MV300) are
  385. implemented.
  386. Parameter <xres_virtual> is required for ProMST or ET4000 cards where
  387. the physical linelength differs from the visible length. With ProMST,
  388. xres_virtual must be set to 2048. For ET4000, xres_virtual depends on the
  389. initialisation of the video-card.
  390. If you're missing a corresponding yres_virtual: the external part is legacy,
  391. therefore we don't support hardware-dependent functions like hardware-scroll,
  392. panning or blanking.
  393. 4.1.7) eclock:
  394. --------------
  395. The external pixel clock attached to the Falcon VIDEL shifter. This
  396. currently works only with the ScreenWonder!
  397. 4.1.8) monitorcap:
  398. -------------------
  399. :Syntax: monitorcap:<vmin>;<vmax>;<hmin>;<hmax>
  400. This describes the capabilities of a multisync monitor. Don't use it
  401. with a fixed-frequency monitor! For now, only the Falcon frame buffer
  402. uses the settings of "monitorcap:".
  403. <vmin> and <vmax> are the minimum and maximum, resp., vertical frequencies
  404. your monitor can work with, in Hz. <hmin> and <hmax> are the same for
  405. the horizontal frequency, in kHz.
  406. The defaults are 58;62;31;32 (VGA compatible).
  407. The defaults for TV/SC1224/SC1435 cover both PAL and NTSC standards.
  408. 4.1.9) keep
  409. ------------
  410. If this option is given, the framebuffer device doesn't do any video
  411. mode calculations and settings on its own. The only Atari fb device
  412. that does this currently is the Falcon.
  413. What you reach with this: Settings for unknown video extensions
  414. aren't overridden by the driver, so you can still use the mode found
  415. when booting, when the driver doesn't know to set this mode itself.
  416. But this also means, that you can't switch video modes anymore...
  417. An example where you may want to use "keep" is the ScreenBlaster for
  418. the Falcon.
  419. 4.2) atamouse=
  420. --------------
  421. :Syntax: atamouse=<x-threshold>,[<y-threshold>]
  422. With this option, you can set the mouse movement reporting threshold.
  423. This is the number of pixels of mouse movement that have to accumulate
  424. before the IKBD sends a new mouse packet to the kernel. Higher values
  425. reduce the mouse interrupt load and thus reduce the chance of keyboard
  426. overruns. Lower values give a slightly faster mouse responses and
  427. slightly better mouse tracking.
  428. You can set the threshold in x and y separately, but usually this is
  429. of little practical use. If there's just one number in the option, it
  430. is used for both dimensions. The default value is 2 for both
  431. thresholds.
  432. 4.3) ataflop=
  433. -------------
  434. :Syntax: ataflop=<drive type>[,<trackbuffering>[,<steprateA>[,<steprateB>]]]
  435. The drive type may be 0, 1, or 2, for DD, HD, and ED, resp. This
  436. setting affects how many buffers are reserved and which formats are
  437. probed (see also below). The default is 1 (HD). Only one drive type
  438. can be selected. If you have two disk drives, select the "better"
  439. type.
  440. The second parameter <trackbuffer> tells the kernel whether to use
  441. track buffering (1) or not (0). The default is machine-dependent:
  442. no for the Medusa and yes for all others.
  443. With the two following parameters, you can change the default
  444. steprate used for drive A and B, resp.
  445. 4.4) atascsi=
  446. -------------
  447. :Syntax: atascsi=<can_queue>[,<cmd_per_lun>[,<scat-gat>[,<host-id>[,<tagged>]]]]
  448. This option sets some parameters for the Atari native SCSI driver.
  449. Generally, any number of arguments can be omitted from the end. And
  450. for each of the numbers, a negative value means "use default". The
  451. defaults depend on whether TT-style or Falcon-style SCSI is used.
  452. Below, defaults are noted as n/m, where the first value refers to
  453. TT-SCSI and the latter to Falcon-SCSI. If an illegal value is given
  454. for one parameter, an error message is printed and that one setting is
  455. ignored (others aren't affected).
  456. <can_queue>:
  457. This is the maximum number of SCSI commands queued internally to the
  458. Atari SCSI driver. A value of 1 effectively turns off the driver
  459. internal multitasking (if it causes problems). Legal values are >=
  460. 1. <can_queue> can be as high as you like, but values greater than
  461. <cmd_per_lun> times the number of SCSI targets (LUNs) you have
  462. don't make sense. Default: 16/8.
  463. <cmd_per_lun>:
  464. Maximum number of SCSI commands issued to the driver for one
  465. logical unit (LUN, usually one SCSI target). Legal values start
  466. from 1. If tagged queuing (see below) is not used, values greater
  467. than 2 don't make sense, but waste memory. Otherwise, the maximum
  468. is the number of command tags available to the driver (currently
  469. 32). Default: 8/1. (Note: Values > 1 seem to cause problems on a
  470. Falcon, cause not yet known.)
  471. The <cmd_per_lun> value at a great part determines the amount of
  472. memory SCSI reserves for itself. The formula is rather
  473. complicated, but I can give you some hints:
  474. no scatter-gather:
  475. cmd_per_lun * 232 bytes
  476. full scatter-gather:
  477. cmd_per_lun * approx. 17 Kbytes
  478. <scat-gat>:
  479. Size of the scatter-gather table, i.e. the number of requests
  480. consecutive on the disk that can be merged into one SCSI command.
  481. Legal values are between 0 and 255. Default: 255/0. Note: This
  482. value is forced to 0 on a Falcon, since scatter-gather isn't
  483. possible with the ST-DMA. Not using scatter-gather hurts
  484. performance significantly.
  485. <host-id>:
  486. The SCSI ID to be used by the initiator (your Atari). This is
  487. usually 7, the highest possible ID. Every ID on the SCSI bus must
  488. be unique. Default: determined at run time: If the NV-RAM checksum
  489. is valid, and bit 7 in byte 30 of the NV-RAM is set, the lower 3
  490. bits of this byte are used as the host ID. (This method is defined
  491. by Atari and also used by some TOS HD drivers.) If the above
  492. isn't given, the default ID is 7. (both, TT and Falcon).
  493. <tagged>:
  494. 0 means turn off tagged queuing support, all other values > 0 mean
  495. use tagged queuing for targets that support it. Default: currently
  496. off, but this may change when tagged queuing handling has been
  497. proved to be reliable.
  498. Tagged queuing means that more than one command can be issued to
  499. one LUN, and the SCSI device itself orders the requests so they
  500. can be performed in optimal order. Not all SCSI devices support
  501. tagged queuing (:-().
  502. 4.5 switches=
  503. -------------
  504. :Syntax: switches=<list of switches>
  505. With this option you can switch some hardware lines that are often
  506. used to enable/disable certain hardware extensions. Examples are
  507. OverScan, overclocking, ...
  508. The <list of switches> is a comma-separated list of the following
  509. items:
  510. ikbd:
  511. set RTS of the keyboard ACIA high
  512. midi:
  513. set RTS of the MIDI ACIA high
  514. snd6:
  515. set bit 6 of the PSG port A
  516. snd7:
  517. set bit 6 of the PSG port A
  518. It doesn't make sense to mention a switch more than once (no
  519. difference to only once), but you can give as many switches as you
  520. want to enable different features. The switch lines are set as early
  521. as possible during kernel initialization (even before determining the
  522. present hardware.)
  523. All of the items can also be prefixed with `ov_`, i.e. `ov_ikbd`,
  524. `ov_midi`, ... These options are meant for switching on an OverScan
  525. video extension. The difference to the bare option is that the
  526. switch-on is done after video initialization, and somehow synchronized
  527. to the HBLANK. A speciality is that ov_ikbd and ov_midi are switched
  528. off before rebooting, so that OverScan is disabled and TOS boots
  529. correctly.
  530. If you give an option both, with and without the `ov_` prefix, the
  531. earlier initialization (`ov_`-less) takes precedence. But the
  532. switching-off on reset still happens in this case.
  533. 5) Options for Amiga Only:
  534. ==========================
  535. 5.1) video=
  536. -----------
  537. :Syntax: video=<fbname>:<sub-options...>
  538. The <fbname> parameter specifies the name of the frame buffer, valid
  539. options are `amifb`, `cyber`, 'virge', `retz3` and `clgen`, provided
  540. that the respective frame buffer devices have been compiled into the
  541. kernel (or compiled as loadable modules). The behavior of the <fbname>
  542. option was changed in 2.1.57 so it is now recommended to specify this
  543. option.
  544. The <sub-options> is a comma-separated list of the sub-options listed
  545. below. This option is organized similar to the Atari version of the
  546. "video"-option (4.1), but knows fewer sub-options.
  547. 5.1.1) video mode
  548. -----------------
  549. Again, similar to the video mode for the Atari (see 4.1.1). Predefined
  550. modes depend on the used frame buffer device.
  551. OCS, ECS and AGA machines all use the color frame buffer. The following
  552. predefined video modes are available:
  553. NTSC modes:
  554. - ntsc : 640x200, 15 kHz, 60 Hz
  555. - ntsc-lace : 640x400, 15 kHz, 60 Hz interlaced
  556. PAL modes:
  557. - pal : 640x256, 15 kHz, 50 Hz
  558. - pal-lace : 640x512, 15 kHz, 50 Hz interlaced
  559. ECS modes:
  560. - multiscan : 640x480, 29 kHz, 57 Hz
  561. - multiscan-lace : 640x960, 29 kHz, 57 Hz interlaced
  562. - euro36 : 640x200, 15 kHz, 72 Hz
  563. - euro36-lace : 640x400, 15 kHz, 72 Hz interlaced
  564. - euro72 : 640x400, 29 kHz, 68 Hz
  565. - euro72-lace : 640x800, 29 kHz, 68 Hz interlaced
  566. - super72 : 800x300, 23 kHz, 70 Hz
  567. - super72-lace : 800x600, 23 kHz, 70 Hz interlaced
  568. - dblntsc-ff : 640x400, 27 kHz, 57 Hz
  569. - dblntsc-lace : 640x800, 27 kHz, 57 Hz interlaced
  570. - dblpal-ff : 640x512, 27 kHz, 47 Hz
  571. - dblpal-lace : 640x1024, 27 kHz, 47 Hz interlaced
  572. - dblntsc : 640x200, 27 kHz, 57 Hz doublescan
  573. - dblpal : 640x256, 27 kHz, 47 Hz doublescan
  574. VGA modes:
  575. - vga : 640x480, 31 kHz, 60 Hz
  576. - vga70 : 640x400, 31 kHz, 70 Hz
  577. Please notice that the ECS and VGA modes require either an ECS or AGA
  578. chipset, and that these modes are limited to 2-bit color for the ECS
  579. chipset and 8-bit color for the AGA chipset.
  580. 5.1.2) depth
  581. ------------
  582. :Syntax: depth:<nr. of bit-planes>
  583. Specify the number of bit-planes for the selected video-mode.
  584. 5.1.3) inverse
  585. --------------
  586. Use inverted display (black on white). Functionally the same as the
  587. "inverse" sub-option for the Atari.
  588. 5.1.4) font
  589. -----------
  590. :Syntax: font:<fontname>
  591. Specify the font to use in text modes. Functionally the same as the
  592. "font" sub-option for the Atari, except that `PEARL8x8` is used instead
  593. of `VGA8x8` if the vertical size of the display is less than 400 pixel
  594. rows.
  595. 5.1.5) monitorcap:
  596. -------------------
  597. :Syntax: monitorcap:<vmin>;<vmax>;<hmin>;<hmax>
  598. This describes the capabilities of a multisync monitor. For now, only
  599. the color frame buffer uses the settings of "monitorcap:".
  600. <vmin> and <vmax> are the minimum and maximum, resp., vertical frequencies
  601. your monitor can work with, in Hz. <hmin> and <hmax> are the same for
  602. the horizontal frequency, in kHz.
  603. The defaults are 50;90;15;38 (Generic Amiga multisync monitor).
  604. 5.2) fd_def_df0=
  605. ----------------
  606. :Syntax: fd_def_df0=<value>
  607. Sets the df0 value for "silent" floppy drives. The value should be in
  608. hexadecimal with "0x" prefix.
  609. 5.3) wd33c93=
  610. -------------
  611. :Syntax: wd33c93=<sub-options...>
  612. These options affect the A590/A2091, A3000 and GVP Series II SCSI
  613. controllers.
  614. The <sub-options> is a comma-separated list of the sub-options listed
  615. below.
  616. 5.3.1) nosync
  617. -------------
  618. :Syntax: nosync:bitmask
  619. bitmask is a byte where the 1st 7 bits correspond with the 7
  620. possible SCSI devices. Set a bit to prevent sync negotiation on that
  621. device. To maintain backwards compatibility, a command-line such as
  622. "wd33c93=255" will be automatically translated to
  623. "wd33c93=nosync:0xff". The default is to disable sync negotiation for
  624. all devices, eg. nosync:0xff.
  625. 5.3.2) period
  626. -------------
  627. :Syntax: period:ns
  628. `ns` is the minimum # of nanoseconds in a SCSI data transfer
  629. period. Default is 500; acceptable values are 250 - 1000.
  630. 5.3.3) disconnect
  631. -----------------
  632. :Syntax: disconnect:x
  633. Specify x = 0 to never allow disconnects, 2 to always allow them.
  634. x = 1 does 'adaptive' disconnects, which is the default and generally
  635. the best choice.
  636. 5.3.4) debug
  637. ------------
  638. :Syntax: debug:x
  639. If `DEBUGGING_ON` is defined, x is a bit mask that causes various
  640. types of debug output to printed - see the DB_xxx defines in
  641. wd33c93.h.
  642. 5.3.5) clock
  643. ------------
  644. :Syntax: clock:x
  645. x = clock input in MHz for WD33c93 chip. Normal values would be from
  646. 8 through 20. The default value depends on your hostadapter(s),
  647. default for the A3000 internal controller is 14, for the A2091 it's 8
  648. and for the GVP hostadapters it's either 8 or 14, depending on the
  649. hostadapter and the SCSI-clock jumper present on some GVP
  650. hostadapters.
  651. 5.3.6) next
  652. -----------
  653. No argument. Used to separate blocks of keywords when there's more
  654. than one wd33c93-based host adapter in the system.
  655. 5.3.7) nodma
  656. ------------
  657. :Syntax: nodma:x
  658. If x is 1 (or if the option is just written as "nodma"), the WD33c93
  659. controller will not use DMA (= direct memory access) to access the
  660. Amiga's memory. This is useful for some systems (like A3000's and
  661. A4000's with the A3640 accelerator, revision 3.0) that have problems
  662. using DMA to chip memory. The default is 0, i.e. to use DMA if
  663. possible.
  664. 5.4) gvp11=
  665. -----------
  666. :Syntax: gvp11=<addr-mask>
  667. The earlier versions of the GVP driver did not handle DMA
  668. address-mask settings correctly which made it necessary for some
  669. people to use this option, in order to get their GVP controller
  670. running under Linux. These problems have hopefully been solved and the
  671. use of this option is now highly unrecommended!
  672. Incorrect use can lead to unpredictable behavior, so please only use
  673. this option if you *know* what you are doing and have a reason to do
  674. so. In any case if you experience problems and need to use this
  675. option, please inform us about it by mailing to the Linux/68k kernel
  676. mailing list.
  677. The address mask set by this option specifies which addresses are
  678. valid for DMA with the GVP Series II SCSI controller. An address is
  679. valid, if no bits are set except the bits that are set in the mask,
  680. too.
  681. Some versions of the GVP can only DMA into a 24 bit address range,
  682. some can address a 25 bit address range while others can use the whole
  683. 32 bit address range for DMA. The correct setting depends on your
  684. controller and should be autodetected by the driver. An example is the
  685. 24 bit region which is specified by a mask of 0x00fffffe.