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Linus Torvalds1da177e2005-04-16 15:20:36 -07001
2 Information regarding the Enhanced IDE drive in Linux 2.6
3
4==============================================================================
5
6
7 The hdparm utility can be used to control various IDE features on a
8 running system. It is packaged separately. Please Look for it on popular
9 linux FTP sites.
10
11
12
13*** IMPORTANT NOTICES: BUGGY IDE CHIPSETS CAN CORRUPT DATA!!
14*** =================
15*** PCI versions of the CMD640 and RZ1000 interfaces are now detected
16*** automatically at startup when PCI BIOS support is configured.
17***
18*** Linux disables the "prefetch" ("readahead") mode of the RZ1000
19*** to prevent data corruption possible due to hardware design flaws.
20***
21*** For the CMD640, linux disables "IRQ unmasking" (hdparm -u1) on any
22*** drive for which the "prefetch" mode of the CMD640 is turned on.
23*** If "prefetch" is disabled (hdparm -p8), then "IRQ unmasking" can be
24*** used again.
25***
26*** For the CMD640, linux disables "32bit I/O" (hdparm -c1) on any drive
27*** for which the "prefetch" mode of the CMD640 is turned off.
28*** If "prefetch" is enabled (hdparm -p9), then "32bit I/O" can be
29*** used again.
30***
31*** The CMD640 is also used on some Vesa Local Bus (VLB) cards, and is *NOT*
32*** automatically detected by Linux. For safe, reliable operation with such
33*** interfaces, one *MUST* use the "ide0=cmd640_vlb" kernel option.
34***
35*** Use of the "serialize" option is no longer necessary.
36
37================================================================================
38Common pitfalls:
39
40- 40-conductor IDE cables are capable of transferring data in DMA modes up to
41 udma2, but no faster.
42
43- If possible devices should be attached to separate channels if they are
44 available. Typically the disk on the first and CD-ROM on the second.
45
46- If you mix devices on the same cable, please consider using similar devices
47 in respect of the data transfer mode they support.
48
49- Even better try to stick to the same vendor and device type on the same
50 cable.
51
52================================================================================
53
54This is the multiple IDE interface driver, as evolved from hd.c.
55
56It supports up to 9 IDE interfaces per default, on one or more IRQs (usually
5714 & 15). There can be up to two drives per interface, as per the ATA-6 spec.
58
59Primary: ide0, port 0x1f0; major=3; hda is minor=0; hdb is minor=64
60Secondary: ide1, port 0x170; major=22; hdc is minor=0; hdd is minor=64
61Tertiary: ide2, port 0x1e8; major=33; hde is minor=0; hdf is minor=64
62Quaternary: ide3, port 0x168; major=34; hdg is minor=0; hdh is minor=64
63fifth.. ide4, usually PCI, probed
64sixth.. ide5, usually PCI, probed
65
66To access devices on interfaces > ide0, device entries please make sure that
67device files for them are present in /dev. If not, please create such
68entries, by using /dev/MAKEDEV.
69
70This driver automatically probes for most IDE interfaces (including all PCI
71ones), for the drives/geometries attached to those interfaces, and for the IRQ
72lines being used by the interfaces (normally 14, 15 for ide0/ide1).
73
74For special cases, interfaces may be specified using kernel "command line"
75options. For example,
76
77 ide3=0x168,0x36e,10 /* ioports 0x168-0x16f,0x36e, irq 10 */
78
79Normally the irq number need not be specified, as ide.c will probe for it:
80
81 ide3=0x168,0x36e /* ioports 0x168-0x16f,0x36e */
82
83The standard port, and irq values are these:
84
85 ide0=0x1f0,0x3f6,14
86 ide1=0x170,0x376,15
87 ide2=0x1e8,0x3ee,11
88 ide3=0x168,0x36e,10
89
90Note that the first parameter reserves 8 contiguous ioports, whereas the
91second value denotes a single ioport. If in doubt, do a 'cat /proc/ioports'.
92
93In all probability the device uses these ports and IRQs if it is attached
94to the appropriate ide channel. Pass the parameter for the correct ide
95channel to the kernel, as explained above.
96
97Any number of interfaces may share a single IRQ if necessary, at a slight
98performance penalty, whether on separate cards or a single VLB card.
99The IDE driver automatically detects and handles this. However, this may
100or may not be harmful to your hardware.. two or more cards driving the same IRQ
101can potentially burn each other's bus driver, though in practice this
102seldom occurs. Be careful, and if in doubt, don't do it!
103
104Drives are normally found by auto-probing and/or examining the CMOS/BIOS data.
105For really weird situations, the apparent (fdisk) geometry can also be specified
106on the kernel "command line" using LILO. The format of such lines is:
107
108 hdx=cyls,heads,sects,wpcom,irq
109or hdx=cdrom
110
111where hdx can be any of hda through hdh, Three values are required
112(cyls,heads,sects). For example:
113
114 hdc=1050,32,64 hdd=cdrom
115
116either {hda,hdb} or {hdc,hdd}. The results of successful auto-probing may
117override the physical geometry/irq specified, though the "original" geometry
118may be retained as the "logical" geometry for partitioning purposes (fdisk).
119
120If the auto-probing during boot time confuses a drive (ie. the drive works
121with hd.c but not with ide.c), then an command line option may be specified
122for each drive for which you'd like the drive to skip the hardware
123probe/identification sequence. For example:
124
125 hdb=noprobe
126or
127 hdc=768,16,32
128 hdc=noprobe
129
130Note that when only one IDE device is attached to an interface, it should be
131jumpered as "single" or "master", *not* "slave". Many folks have had
132"trouble" with cdroms because of this requirement, so the driver now probes
133for both units, though success is more likely when the drive is jumpered
134correctly.
135
136Courtesy of Scott Snyder and others, the driver supports ATAPI cdrom drives
137such as the NEC-260 and the new MITSUMI triple/quad speed drives.
138Such drives will be identified at boot time, just like a hard disk.
139
140If for some reason your cdrom drive is *not* found at boot time, you can force
141the probe to look harder by supplying a kernel command line parameter
142via LILO, such as:
143
144 hdc=cdrom /* hdc = "master" on second interface */
145or
146 hdd=cdrom /* hdd = "slave" on second interface */
147
148For example, a GW2000 system might have a hard drive on the primary
149interface (/dev/hda) and an IDE cdrom drive on the secondary interface
150(/dev/hdc). To mount a CD in the cdrom drive, one would use something like:
151
152 ln -sf /dev/hdc /dev/cdrom
153 mkdir /mnt/cdrom
154 mount /dev/cdrom /mnt/cdrom -t iso9660 -o ro
155
156If, after doing all of the above, mount doesn't work and you see
157errors from the driver (with dmesg) complaining about `status=0xff',
158this means that the hardware is not responding to the driver's attempts
159to read it. One of the following is probably the problem:
160
161 - Your hardware is broken.
162
163 - You are using the wrong address for the device, or you have the
164 drive jumpered wrong. Review the configuration instructions above.
165
166 - Your IDE controller requires some nonstandard initialization sequence
167 before it will work properly. If this is the case, there will often
168 be a separate MS-DOS driver just for the controller. IDE interfaces
169 on sound cards usually fall into this category. Such configurations
170 can often be made to work by first booting MS-DOS, loading the
171 appropriate drivers, and then warm-booting linux (without powering
172 off). This can be automated using loadlin in the MS-DOS autoexec.
173
174If you always get timeout errors, interrupts from the drive are probably
175not making it to the host. Check how you have the hardware jumpered
176and make sure it matches what the driver expects (see the configuration
177instructions above). If you have a PCI system, also check the BIOS
178setup; I've had one report of a system which was shipped with IRQ 15
179disabled by the BIOS.
180
181The kernel is able to execute binaries directly off of the cdrom,
182provided it is mounted with the default block size of 1024 (as above).
183
184Please pass on any feedback on any of this stuff to the maintainer,
185whose address can be found in linux/MAINTAINERS.
186
187Note that if BOTH hd.c and ide.c are configured into the kernel,
188hd.c will normally be allowed to control the primary IDE interface.
189This is useful for older hardware that may be incompatible with ide.c,
190and still allows newer hardware to run on the 2nd/3rd/4th IDE ports
191under control of ide.c. To have ide.c also "take over" the primary
192IDE port in this situation, use the "command line" parameter: ide0=0x1f0
193
194The IDE driver is modularized. The high level disk/CD-ROM/tape/floppy
195drivers can always be compiled as loadable modules, the chipset drivers
196can only be compiled into the kernel, and the core code (ide.c) can be
197compiled as a loadable module provided no chipset support is needed.
198
199When using ide.c as a module in combination with kmod, add:
200
201 alias block-major-3 ide-probe
202
203to /etc/modprobe.conf.
204
205When ide.c is used as a module, you can pass command line parameters to the
206driver using the "options=" keyword to insmod, while replacing any ',' with
207';'. For example:
208
209 insmod ide.o options="ide0=serialize ide1=serialize ide2=0x1e8;0x3ee;11"
210
211
212================================================================================
213
214Summary of ide driver parameters for kernel command line
215--------------------------------------------------------
216
217 "hdx=" is recognized for all "x" from "a" to "h", such as "hdc".
218
219 "idex=" is recognized for all "x" from "0" to "3", such as "ide1".
220
221 "hdx=noprobe" : drive may be present, but do not probe for it
222
223 "hdx=none" : drive is NOT present, ignore cmos and do not probe
224
225 "hdx=nowerr" : ignore the WRERR_STAT bit on this drive
226
227 "hdx=cdrom" : drive is present, and is a cdrom drive
228
229 "hdx=cyl,head,sect" : disk drive is present, with specified geometry
230
231 "hdx=remap" : remap access of sector 0 to sector 1 (for EZDrive)
232
233 "hdx=remap63" : remap the drive: add 63 to all sector numbers
234 (for DM OnTrack)
Bartlomiej Zolnierkiewiczb6209a92007-03-03 17:48:55 +0100235
236 "idex=noautotune" : driver will NOT attempt to tune interface speed
237
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 "hdx=autotune" : driver will attempt to tune interface speed
239 to the fastest PIO mode supported,
240 if possible for this drive only.
241 Not fully supported by all chipset types,
242 and quite likely to cause trouble with
243 older/odd IDE drives.
244
Bartlomiej Zolnierkiewiczc2237012007-10-16 22:29:58 +0200245 "hdx=nodma" : disallow DMA
246
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 "hdx=swapdata" : when the drive is a disk, byte swap all data
248
249 "hdx=bswap" : same as above..........
250
251 "hdx=scsi" : the return of the ide-scsi flag, this is useful for
252 allowing ide-floppy, ide-tape, and ide-cdrom|writers
253 to use ide-scsi emulation on a device specific option.
254
255 "idebus=xx" : inform IDE driver of VESA/PCI bus speed in MHz,
256 where "xx" is between 20 and 66 inclusive,
257 used when tuning chipset PIO modes.
258 For PCI bus, 25 is correct for a P75 system,
259 30 is correct for P90,P120,P180 systems,
260 and 33 is used for P100,P133,P166 systems.
261 If in doubt, use idebus=33 for PCI.
262 As for VLB, it is safest to not specify it.
263 Bigger values are safer than smaller ones.
264
265 "idex=noprobe" : do not attempt to access/use this interface
266
267 "idex=base" : probe for an interface at the addr specified,
268 where "base" is usually 0x1f0 or 0x170
269 and "ctl" is assumed to be "base"+0x206
270
271 "idex=base,ctl" : specify both base and ctl
272
273 "idex=base,ctl,irq" : specify base, ctl, and irq number
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
275 "idex=serialize" : do not overlap operations on idex. Please note
276 that you will have to specify this option for
Matt LaPlanted6bc8ac2006-10-03 22:54:15 +0200277 both the respective primary and secondary channel
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 to take effect.
279
280 "idex=four" : four drives on idex and ide(x^1) share same ports
281
282 "idex=reset" : reset interface after probe
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283
284 "idex=ata66" : informs the interface that it has an 80c cable
285 for chipsets that are ATA-66 capable, but the
286 ability to bit test for detection is currently
287 unknown.
288
289 "ide=reverse" : formerly called to pci sub-system, but now local.
290
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291The following are valid ONLY on ide0, which usually corresponds
292to the first ATA interface found on the particular host, and the defaults for
293the base,ctl ports must not be altered.
294
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 "ide0=cmd640_vlb" : *REQUIRED* for VLB cards with the CMD640 chip
296 (not for PCI -- automatically detected)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297
298 "ide=doubler" : probe/support IDE doublers on Amiga
299
300There may be more options than shown -- use the source, Luke!
301
302Everything else is rejected with a "BAD OPTION" message.
303
Bartlomiej Zolnierkiewicz84913882007-03-03 17:48:55 +0100304For legacy IDE VLB host drivers (ali14xx/dtc2278/ht6560b/qd65xx/umc8672)
305you need to explicitly enable probing by using "probe" kernel parameter,
306i.e. to enable probing for ALI M14xx chipsets (ali14xx host driver) use:
307
308* "ali14xx.probe" boot option when ali14xx driver is built-in the kernel
309
310* "probe" module parameter when ali14xx driver is compiled as module
311 ("modprobe ali14xx probe")
312
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313================================================================================
314
315IDE ATAPI streaming tape driver
316-------------------------------
317
318This driver is a part of the Linux ide driver and works in co-operation
319with linux/drivers/block/ide.c.
320
321The driver, in co-operation with ide.c, basically traverses the
322request-list for the block device interface. The character device
323interface, on the other hand, creates new requests, adds them
324to the request-list of the block device, and waits for their completion.
325
326Pipelined operation mode is now supported on both reads and writes.
327
328The block device major and minor numbers are determined from the
329tape's relative position in the ide interfaces, as explained in ide.c.
330
331The character device interface consists of the following devices:
332
333 ht0 major 37, minor 0 first IDE tape, rewind on close.
334 ht1 major 37, minor 1 second IDE tape, rewind on close.
335 ...
336 nht0 major 37, minor 128 first IDE tape, no rewind on close.
337 nht1 major 37, minor 129 second IDE tape, no rewind on close.
338 ...
339
340Run /dev/MAKEDEV to create the above entries.
341
342The general magnetic tape commands compatible interface, as defined by
343include/linux/mtio.h, is accessible through the character device.
344
345General ide driver configuration options, such as the interrupt-unmask
346flag, can be configured by issuing an ioctl to the block device interface,
347as any other ide device.
348
349Our own ide-tape ioctl's can be issued to either the block device or
350the character device interface.
351
352Maximal throughput with minimal bus load will usually be achieved in the
353following scenario:
354
355 1. ide-tape is operating in the pipelined operation mode.
356 2. No buffering is performed by the user backup program.
357
358
359
360================================================================================
361
362Some Terminology
363----------------
364IDE = Integrated Drive Electronics, meaning that each drive has a built-in
365controller, which is why an "IDE interface card" is not a "controller card".
366
367ATA = AT (the old IBM 286 computer) Attachment Interface, a draft American
368National Standard for connecting hard drives to PCs. This is the official
369name for "IDE".
370
371The latest standards define some enhancements, known as the ATA-6 spec,
372which grew out of vendor-specific "Enhanced IDE" (EIDE) implementations.
373
374ATAPI = ATA Packet Interface, a new protocol for controlling the drives,
375similar to SCSI protocols, created at the same time as the ATA2 standard.
376ATAPI is currently used for controlling CDROM, TAPE and FLOPPY (ZIP or
377LS120/240) devices, removable R/W cartridges, and for high capacity hard disk
378drives.
379
380mlord@pobox.com
381--
382
383Wed Apr 17 22:52:44 CEST 2002 edited by Marcin Dalecki, the current
384maintainer.
385
Matt LaPlante4ae0edc2006-11-30 04:58:40 +0100386Wed Aug 20 22:31:29 CEST 2003 updated ide boot options to current ide.c
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387comments at 2.6.0-test4 time. Maciej Soltysiak <solt@dns.toxicfilms.tv>