ide.txt 15 KB

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  1. Information regarding the Enhanced IDE drive in Linux 2.6
  2. ==============================================================================
  3. The hdparm utility can be used to control various IDE features on a
  4. running system. It is packaged separately. Please Look for it on popular
  5. linux FTP sites.
  6. *** IMPORTANT NOTICES: BUGGY IDE CHIPSETS CAN CORRUPT DATA!!
  7. *** =================
  8. *** PCI versions of the CMD640 and RZ1000 interfaces are now detected
  9. *** automatically at startup when PCI BIOS support is configured.
  10. ***
  11. *** Linux disables the "prefetch" ("readahead") mode of the RZ1000
  12. *** to prevent data corruption possible due to hardware design flaws.
  13. ***
  14. *** For the CMD640, linux disables "IRQ unmasking" (hdparm -u1) on any
  15. *** drive for which the "prefetch" mode of the CMD640 is turned on.
  16. *** If "prefetch" is disabled (hdparm -p8), then "IRQ unmasking" can be
  17. *** used again.
  18. ***
  19. *** For the CMD640, linux disables "32bit I/O" (hdparm -c1) on any drive
  20. *** for which the "prefetch" mode of the CMD640 is turned off.
  21. *** If "prefetch" is enabled (hdparm -p9), then "32bit I/O" can be
  22. *** used again.
  23. ***
  24. *** The CMD640 is also used on some Vesa Local Bus (VLB) cards, and is *NOT*
  25. *** automatically detected by Linux. For safe, reliable operation with such
  26. *** interfaces, one *MUST* use the "ide0=cmd640_vlb" kernel option.
  27. ***
  28. *** Use of the "serialize" option is no longer necessary.
  29. ================================================================================
  30. Common pitfalls:
  31. - 40-conductor IDE cables are capable of transferring data in DMA modes up to
  32. udma2, but no faster.
  33. - If possible devices should be attached to separate channels if they are
  34. available. Typically the disk on the first and CD-ROM on the second.
  35. - If you mix devices on the same cable, please consider using similar devices
  36. in respect of the data transfer mode they support.
  37. - Even better try to stick to the same vendor and device type on the same
  38. cable.
  39. ================================================================================
  40. This is the multiple IDE interface driver, as evolved from hd.c.
  41. It supports up to 9 IDE interfaces per default, on one or more IRQs (usually
  42. 14 & 15). There can be up to two drives per interface, as per the ATA-6 spec.
  43. Primary: ide0, port 0x1f0; major=3; hda is minor=0; hdb is minor=64
  44. Secondary: ide1, port 0x170; major=22; hdc is minor=0; hdd is minor=64
  45. Tertiary: ide2, port 0x1e8; major=33; hde is minor=0; hdf is minor=64
  46. Quaternary: ide3, port 0x168; major=34; hdg is minor=0; hdh is minor=64
  47. fifth.. ide4, usually PCI, probed
  48. sixth.. ide5, usually PCI, probed
  49. To access devices on interfaces > ide0, device entries please make sure that
  50. device files for them are present in /dev. If not, please create such
  51. entries, by using /dev/MAKEDEV.
  52. This driver automatically probes for most IDE interfaces (including all PCI
  53. ones), for the drives/geometries attached to those interfaces, and for the IRQ
  54. lines being used by the interfaces (normally 14, 15 for ide0/ide1).
  55. For special cases, interfaces may be specified using kernel "command line"
  56. options. For example,
  57. ide3=0x168,0x36e,10 /* ioports 0x168-0x16f,0x36e, irq 10 */
  58. Normally the irq number need not be specified, as ide.c will probe for it:
  59. ide3=0x168,0x36e /* ioports 0x168-0x16f,0x36e */
  60. The standard port, and irq values are these:
  61. ide0=0x1f0,0x3f6,14
  62. ide1=0x170,0x376,15
  63. ide2=0x1e8,0x3ee,11
  64. ide3=0x168,0x36e,10
  65. Note that the first parameter reserves 8 contiguous ioports, whereas the
  66. second value denotes a single ioport. If in doubt, do a 'cat /proc/ioports'.
  67. In all probability the device uses these ports and IRQs if it is attached
  68. to the appropriate ide channel. Pass the parameter for the correct ide
  69. channel to the kernel, as explained above.
  70. Any number of interfaces may share a single IRQ if necessary, at a slight
  71. performance penalty, whether on separate cards or a single VLB card.
  72. The IDE driver automatically detects and handles this. However, this may
  73. or may not be harmful to your hardware.. two or more cards driving the same IRQ
  74. can potentially burn each other's bus driver, though in practice this
  75. seldom occurs. Be careful, and if in doubt, don't do it!
  76. Drives are normally found by auto-probing and/or examining the CMOS/BIOS data.
  77. For really weird situations, the apparent (fdisk) geometry can also be specified
  78. on the kernel "command line" using LILO. The format of such lines is:
  79. hdx=cyls,heads,sects,wpcom,irq
  80. or hdx=cdrom
  81. where hdx can be any of hda through hdh, Three values are required
  82. (cyls,heads,sects). For example:
  83. hdc=1050,32,64 hdd=cdrom
  84. either {hda,hdb} or {hdc,hdd}. The results of successful auto-probing may
  85. override the physical geometry/irq specified, though the "original" geometry
  86. may be retained as the "logical" geometry for partitioning purposes (fdisk).
  87. If the auto-probing during boot time confuses a drive (ie. the drive works
  88. with hd.c but not with ide.c), then an command line option may be specified
  89. for each drive for which you'd like the drive to skip the hardware
  90. probe/identification sequence. For example:
  91. hdb=noprobe
  92. or
  93. hdc=768,16,32
  94. hdc=noprobe
  95. Note that when only one IDE device is attached to an interface, it should be
  96. jumpered as "single" or "master", *not* "slave". Many folks have had
  97. "trouble" with cdroms because of this requirement, so the driver now probes
  98. for both units, though success is more likely when the drive is jumpered
  99. correctly.
  100. Courtesy of Scott Snyder and others, the driver supports ATAPI cdrom drives
  101. such as the NEC-260 and the new MITSUMI triple/quad speed drives.
  102. Such drives will be identified at boot time, just like a hard disk.
  103. If for some reason your cdrom drive is *not* found at boot time, you can force
  104. the probe to look harder by supplying a kernel command line parameter
  105. via LILO, such as:
  106. hdc=cdrom /* hdc = "master" on second interface */
  107. or
  108. hdd=cdrom /* hdd = "slave" on second interface */
  109. For example, a GW2000 system might have a hard drive on the primary
  110. interface (/dev/hda) and an IDE cdrom drive on the secondary interface
  111. (/dev/hdc). To mount a CD in the cdrom drive, one would use something like:
  112. ln -sf /dev/hdc /dev/cdrom
  113. mkdir /mnt/cdrom
  114. mount /dev/cdrom /mnt/cdrom -t iso9660 -o ro
  115. If, after doing all of the above, mount doesn't work and you see
  116. errors from the driver (with dmesg) complaining about `status=0xff',
  117. this means that the hardware is not responding to the driver's attempts
  118. to read it. One of the following is probably the problem:
  119. - Your hardware is broken.
  120. - You are using the wrong address for the device, or you have the
  121. drive jumpered wrong. Review the configuration instructions above.
  122. - Your IDE controller requires some nonstandard initialization sequence
  123. before it will work properly. If this is the case, there will often
  124. be a separate MS-DOS driver just for the controller. IDE interfaces
  125. on sound cards usually fall into this category. Such configurations
  126. can often be made to work by first booting MS-DOS, loading the
  127. appropriate drivers, and then warm-booting linux (without powering
  128. off). This can be automated using loadlin in the MS-DOS autoexec.
  129. If you always get timeout errors, interrupts from the drive are probably
  130. not making it to the host. Check how you have the hardware jumpered
  131. and make sure it matches what the driver expects (see the configuration
  132. instructions above). If you have a PCI system, also check the BIOS
  133. setup; I've had one report of a system which was shipped with IRQ 15
  134. disabled by the BIOS.
  135. The kernel is able to execute binaries directly off of the cdrom,
  136. provided it is mounted with the default block size of 1024 (as above).
  137. Please pass on any feedback on any of this stuff to the maintainer,
  138. whose address can be found in linux/MAINTAINERS.
  139. Note that if BOTH hd.c and ide.c are configured into the kernel,
  140. hd.c will normally be allowed to control the primary IDE interface.
  141. This is useful for older hardware that may be incompatible with ide.c,
  142. and still allows newer hardware to run on the 2nd/3rd/4th IDE ports
  143. under control of ide.c. To have ide.c also "take over" the primary
  144. IDE port in this situation, use the "command line" parameter: ide0=0x1f0
  145. The IDE driver is modularized. The high level disk/CD-ROM/tape/floppy
  146. drivers can always be compiled as loadable modules, the chipset drivers
  147. can only be compiled into the kernel, and the core code (ide.c) can be
  148. compiled as a loadable module provided no chipset support is needed.
  149. When using ide.c as a module in combination with kmod, add:
  150. alias block-major-3 ide-probe
  151. to /etc/modprobe.conf.
  152. When ide.c is used as a module, you can pass command line parameters to the
  153. driver using the "options=" keyword to insmod, while replacing any ',' with
  154. ';'. For example:
  155. insmod ide.o options="ide0=serialize ide1=serialize ide2=0x1e8;0x3ee;11"
  156. ================================================================================
  157. Summary of ide driver parameters for kernel command line
  158. --------------------------------------------------------
  159. "hdx=" is recognized for all "x" from "a" to "h", such as "hdc".
  160. "idex=" is recognized for all "x" from "0" to "3", such as "ide1".
  161. "hdx=noprobe" : drive may be present, but do not probe for it
  162. "hdx=none" : drive is NOT present, ignore cmos and do not probe
  163. "hdx=nowerr" : ignore the WRERR_STAT bit on this drive
  164. "hdx=cdrom" : drive is present, and is a cdrom drive
  165. "hdx=cyl,head,sect" : disk drive is present, with specified geometry
  166. "hdx=remap" : remap access of sector 0 to sector 1 (for EZDrive)
  167. "hdx=remap63" : remap the drive: add 63 to all sector numbers
  168. (for DM OnTrack)
  169. "idex=noautotune" : driver will NOT attempt to tune interface speed
  170. "hdx=autotune" : driver will attempt to tune interface speed
  171. to the fastest PIO mode supported,
  172. if possible for this drive only.
  173. Not fully supported by all chipset types,
  174. and quite likely to cause trouble with
  175. older/odd IDE drives.
  176. "hdx=swapdata" : when the drive is a disk, byte swap all data
  177. "hdx=bswap" : same as above..........
  178. "hdx=scsi" : the return of the ide-scsi flag, this is useful for
  179. allowing ide-floppy, ide-tape, and ide-cdrom|writers
  180. to use ide-scsi emulation on a device specific option.
  181. "idebus=xx" : inform IDE driver of VESA/PCI bus speed in MHz,
  182. where "xx" is between 20 and 66 inclusive,
  183. used when tuning chipset PIO modes.
  184. For PCI bus, 25 is correct for a P75 system,
  185. 30 is correct for P90,P120,P180 systems,
  186. and 33 is used for P100,P133,P166 systems.
  187. If in doubt, use idebus=33 for PCI.
  188. As for VLB, it is safest to not specify it.
  189. Bigger values are safer than smaller ones.
  190. "idex=noprobe" : do not attempt to access/use this interface
  191. "idex=base" : probe for an interface at the addr specified,
  192. where "base" is usually 0x1f0 or 0x170
  193. and "ctl" is assumed to be "base"+0x206
  194. "idex=base,ctl" : specify both base and ctl
  195. "idex=base,ctl,irq" : specify base, ctl, and irq number
  196. "idex=serialize" : do not overlap operations on idex. Please note
  197. that you will have to specify this option for
  198. both the respective primary and secondary channel
  199. to take effect.
  200. "idex=four" : four drives on idex and ide(x^1) share same ports
  201. "idex=reset" : reset interface after probe
  202. "idex=dma" : automatically configure/use DMA if possible.
  203. "idex=ata66" : informs the interface that it has an 80c cable
  204. for chipsets that are ATA-66 capable, but the
  205. ability to bit test for detection is currently
  206. unknown.
  207. "ide=reverse" : formerly called to pci sub-system, but now local.
  208. "ide=nodma" : disable DMA globally for the IDE subsystem.
  209. The following are valid ONLY on ide0, which usually corresponds
  210. to the first ATA interface found on the particular host, and the defaults for
  211. the base,ctl ports must not be altered.
  212. "ide0=cmd640_vlb" : *REQUIRED* for VLB cards with the CMD640 chip
  213. (not for PCI -- automatically detected)
  214. "ide=doubler" : probe/support IDE doublers on Amiga
  215. There may be more options than shown -- use the source, Luke!
  216. Everything else is rejected with a "BAD OPTION" message.
  217. For legacy IDE VLB host drivers (ali14xx/dtc2278/ht6560b/qd65xx/umc8672)
  218. you need to explicitly enable probing by using "probe" kernel parameter,
  219. i.e. to enable probing for ALI M14xx chipsets (ali14xx host driver) use:
  220. * "ali14xx.probe" boot option when ali14xx driver is built-in the kernel
  221. * "probe" module parameter when ali14xx driver is compiled as module
  222. ("modprobe ali14xx probe")
  223. ================================================================================
  224. IDE ATAPI streaming tape driver
  225. -------------------------------
  226. This driver is a part of the Linux ide driver and works in co-operation
  227. with linux/drivers/block/ide.c.
  228. The driver, in co-operation with ide.c, basically traverses the
  229. request-list for the block device interface. The character device
  230. interface, on the other hand, creates new requests, adds them
  231. to the request-list of the block device, and waits for their completion.
  232. Pipelined operation mode is now supported on both reads and writes.
  233. The block device major and minor numbers are determined from the
  234. tape's relative position in the ide interfaces, as explained in ide.c.
  235. The character device interface consists of the following devices:
  236. ht0 major 37, minor 0 first IDE tape, rewind on close.
  237. ht1 major 37, minor 1 second IDE tape, rewind on close.
  238. ...
  239. nht0 major 37, minor 128 first IDE tape, no rewind on close.
  240. nht1 major 37, minor 129 second IDE tape, no rewind on close.
  241. ...
  242. Run /dev/MAKEDEV to create the above entries.
  243. The general magnetic tape commands compatible interface, as defined by
  244. include/linux/mtio.h, is accessible through the character device.
  245. General ide driver configuration options, such as the interrupt-unmask
  246. flag, can be configured by issuing an ioctl to the block device interface,
  247. as any other ide device.
  248. Our own ide-tape ioctl's can be issued to either the block device or
  249. the character device interface.
  250. Maximal throughput with minimal bus load will usually be achieved in the
  251. following scenario:
  252. 1. ide-tape is operating in the pipelined operation mode.
  253. 2. No buffering is performed by the user backup program.
  254. ================================================================================
  255. Some Terminology
  256. ----------------
  257. IDE = Integrated Drive Electronics, meaning that each drive has a built-in
  258. controller, which is why an "IDE interface card" is not a "controller card".
  259. ATA = AT (the old IBM 286 computer) Attachment Interface, a draft American
  260. National Standard for connecting hard drives to PCs. This is the official
  261. name for "IDE".
  262. The latest standards define some enhancements, known as the ATA-6 spec,
  263. which grew out of vendor-specific "Enhanced IDE" (EIDE) implementations.
  264. ATAPI = ATA Packet Interface, a new protocol for controlling the drives,
  265. similar to SCSI protocols, created at the same time as the ATA2 standard.
  266. ATAPI is currently used for controlling CDROM, TAPE and FLOPPY (ZIP or
  267. LS120/240) devices, removable R/W cartridges, and for high capacity hard disk
  268. drives.
  269. mlord@pobox.com
  270. --
  271. Wed Apr 17 22:52:44 CEST 2002 edited by Marcin Dalecki, the current
  272. maintainer.
  273. Wed Aug 20 22:31:29 CEST 2003 updated ide boot options to current ide.c
  274. comments at 2.6.0-test4 time. Maciej Soltysiak <solt@dns.toxicfilms.tv>