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Based on kernel version 3.15.4. Page generated on 2014-07-07 09:03 EST.

1	
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 "cmd640.probe_vlb" kernel option.
34	***
35	***  Use of the "serialize" option is no longer necessary.
36	
37	================================================================================
38	Common 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	
54	This is the multiple IDE interface driver, as evolved from hd.c.
55	
56	It supports up to 9 IDE interfaces per default, on one or more IRQs (usually
57	14 & 15).  There can be up to two drives per interface, as per the ATA-6 spec.
58	
59	Primary:    ide0, port 0x1f0; major=3;  hda is minor=0; hdb is minor=64
60	Secondary:  ide1, port 0x170; major=22; hdc is minor=0; hdd is minor=64
61	Tertiary:   ide2, port 0x1e8; major=33; hde is minor=0; hdf is minor=64
62	Quaternary: ide3, port 0x168; major=34; hdg is minor=0; hdh is minor=64
63	fifth..     ide4, usually PCI, probed
64	sixth..     ide5, usually PCI, probed
65	
66	To access devices on interfaces > ide0, device entries please make sure that
67	device files for them are present in /dev.  If not, please create such
68	entries, by using /dev/MAKEDEV.
69	
70	This driver automatically probes for most IDE interfaces (including all PCI
71	ones), for the drives/geometries attached to those interfaces, and for the IRQ
72	lines being used by the interfaces (normally 14, 15 for ide0/ide1).
73	
74	Any number of interfaces may share a single IRQ if necessary, at a slight
75	performance penalty, whether on separate cards or a single VLB card.
76	The IDE driver automatically detects and handles this.  However, this may
77	or may not be harmful to your hardware.. two or more cards driving the same IRQ
78	can potentially burn each other's bus driver, though in practice this
79	seldom occurs.  Be careful, and if in doubt, don't do it!
80	
81	Drives are normally found by auto-probing and/or examining the CMOS/BIOS data.
82	For really weird situations, the apparent (fdisk) geometry can also be specified
83	on the kernel "command line" using LILO.  The format of such lines is:
84	
85		ide_core.chs=[interface_number.device_number]:cyls,heads,sects
86	or	ide_core.cdrom=[interface_number.device_number]
87	
88	For example:
89	
90		ide_core.chs=1.0:1050,32,64  ide_core.cdrom=1.1
91	
92	The results of successful auto-probing may override the physical geometry/irq
93	specified, though the "original" geometry may be retained as the "logical"
94	geometry for partitioning purposes (fdisk).
95	
96	If the auto-probing during boot time confuses a drive (ie. the drive works
97	with hd.c but not with ide.c), then an command line option may be specified
98	for each drive for which you'd like the drive to skip the hardware
99	probe/identification sequence.  For example:
100	
101		ide_core.noprobe=0.1
102	or
103		ide_core.chs=1.0:768,16,32
104		ide_core.noprobe=1.0
105	
106	Note that when only one IDE device is attached to an interface, it should be
107	jumpered as "single" or "master", *not* "slave".  Many folks have had
108	"trouble" with cdroms because of this requirement, so the driver now probes
109	for both units, though success is more likely when the drive is jumpered
110	correctly.
111	
112	Courtesy of Scott Snyder and others, the driver supports ATAPI cdrom drives
113	such as the NEC-260 and the new MITSUMI triple/quad speed drives.
114	Such drives will be identified at boot time, just like a hard disk.
115	
116	If for some reason your cdrom drive is *not* found at boot time, you can force
117	the probe to look harder by supplying a kernel command line parameter
118	via LILO, such as:
119	
120		ide_core.cdrom=1.0	/* "master" on second interface (hdc) */
121	or
122		ide_core.cdrom=1.1	/* "slave" on second interface (hdd) */
123	
124	For example, a GW2000 system might have a hard drive on the primary
125	interface (/dev/hda) and an IDE cdrom drive on the secondary interface
126	(/dev/hdc).  To mount a CD in the cdrom drive, one would use something like:
127	
128		ln -sf /dev/hdc /dev/cdrom
129		mkdir /mnt/cdrom
130		mount /dev/cdrom /mnt/cdrom -t iso9660 -o ro
131	
132	If, after doing all of the above, mount doesn't work and you see
133	errors from the driver (with dmesg) complaining about `status=0xff',
134	this means that the hardware is not responding to the driver's attempts
135	to read it.  One of the following is probably the problem:
136	
137	  - Your hardware is broken.
138	
139	  - You are using the wrong address for the device, or you have the
140	    drive jumpered wrong.  Review the configuration instructions above.
141	
142	  - Your IDE controller requires some nonstandard initialization sequence
143	    before it will work properly.  If this is the case, there will often
144	    be a separate MS-DOS driver just for the controller.  IDE interfaces
145	    on sound cards usually fall into this category.  Such configurations
146	    can often be made to work by first booting MS-DOS, loading the
147	    appropriate drivers, and then warm-booting linux (without powering
148	    off).  This can be automated using loadlin in the MS-DOS autoexec.
149	
150	If you always get timeout errors, interrupts from the drive are probably
151	not making it to the host.  Check how you have the hardware jumpered
152	and make sure it matches what the driver expects (see the configuration
153	instructions above).  If you have a PCI system, also check the BIOS
154	setup; I've had one report of a system which was shipped with IRQ 15
155	disabled by the BIOS.
156	
157	The kernel is able to execute binaries directly off of the cdrom,
158	provided it is mounted with the default block size of 1024 (as above).
159	
160	Please pass on any feedback on any of this stuff to the maintainer,
161	whose address can be found in linux/MAINTAINERS.
162	
163	The IDE driver is modularized.  The high level disk/CD-ROM/tape/floppy
164	drivers can always be compiled as loadable modules, the chipset drivers
165	can only be compiled into the kernel, and the core code (ide.c) can be
166	compiled as a loadable module provided no chipset support is needed.
167	
168	When using ide.c as a module in combination with kmod, add:
169	
170		alias block-major-3 ide-probe
171	
172	to a configuration file in /etc/modprobe.d/.
173	
174	When ide.c is used as a module, you can pass command line parameters to the
175	driver using the "options=" keyword to insmod, while replacing any ',' with
176	';'.
177	
178	
179	================================================================================
180	
181	Summary of ide driver parameters for kernel command line
182	--------------------------------------------------------
183	
184	For legacy IDE VLB host drivers (ali14xx/dtc2278/ht6560b/qd65xx/umc8672)
185	you need to explicitly enable probing by using "probe" kernel parameter,
186	i.e. to enable probing for ALI M14xx chipsets (ali14xx host driver) use:
187	
188	* "ali14xx.probe" boot option when ali14xx driver is built-in the kernel
189	
190	* "probe" module parameter when ali14xx driver is compiled as module
191	  ("modprobe ali14xx probe")
192	
193	Also for legacy CMD640 host driver (cmd640) you need to use "probe_vlb"
194	kernel paremeter to enable probing for VLB version of the chipset (PCI ones
195	are detected automatically).
196	
197	You also need to use "probe" kernel parameter for ide-4drives driver
198	(support for IDE generic chipset with four drives on one port).
199	
200	To enable support for IDE doublers on Amiga use "doubler" kernel parameter
201	for gayle host driver (i.e. "gayle.doubler" if the driver is built-in).
202	
203	To force ignoring cable detection (this should be needed only if you're using
204	short 40-wires cable which cannot be automatically detected - if this is not
205	a case please report it as a bug instead) use "ignore_cable" kernel parameter:
206	
207	* "ide_core.ignore_cable=[interface_number]" boot option if IDE is built-in
208	  (i.e. "ide_core.ignore_cable=1" to force ignoring cable for "ide1")
209	
210	* "ignore_cable=[interface_number]" module parameter (for ide_core module)
211	  if IDE is compiled as module
212	
213	Other kernel parameters for ide_core are:
214	
215	* "nodma=[interface_number.device_number]" to disallow DMA for a device
216	
217	* "noflush=[interface_number.device_number]" to disable flush requests
218	
219	* "nohpa=[interface_number.device_number]" to disable Host Protected Area
220	
221	* "noprobe=[interface_number.device_number]" to skip probing
222	
223	* "nowerr=[interface_number.device_number]" to ignore the WRERR_STAT bit
224	
225	* "cdrom=[interface_number.device_number]" to force device as a CD-ROM
226	
227	* "chs=[interface_number.device_number]" to force device as a disk (using CHS)
228	
229	================================================================================
230	
231	Some Terminology
232	----------------
233	IDE = Integrated Drive Electronics, meaning that each drive has a built-in
234	controller, which is why an "IDE interface card" is not a "controller card".
235	
236	ATA = AT (the old IBM 286 computer) Attachment Interface, a draft American
237	National Standard for connecting hard drives to PCs.  This is the official
238	name for "IDE".
239	
240	The latest standards define some enhancements, known as the ATA-6 spec,
241	which grew out of vendor-specific "Enhanced IDE" (EIDE) implementations.
242	
243	ATAPI = ATA Packet Interface, a new protocol for controlling the drives,
244	similar to SCSI protocols, created at the same time as the ATA2 standard.
245	ATAPI is currently used for controlling CDROM, TAPE and FLOPPY (ZIP or
246	LS120/240) devices, removable R/W cartridges, and for high capacity hard disk
247	drives.
248	
249	mlord@pobox.com
250	--
251	
252	Wed Apr 17 22:52:44 CEST 2002 edited by Marcin Dalecki, the current
253	maintainer.
254	
255	Wed Aug 20 22:31:29 CEST 2003 updated ide boot options to current ide.c
256	comments at 2.6.0-test4 time. Maciej Soltysiak <solt@dns.toxicfilms.tv>
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