Based on kernel version 2.6.26. Page generated on 2008-07-16 21:13 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 For special cases, interfaces may be specified using kernel "command line" 75 options. For example, 76 77 ide3=0x168,0x36e,10 /* ioports 0x168-0x16f,0x36e, irq 10 */ 78 79 Normally the irq number need not be specified, as ide.c will probe for it: 80 81 ide3=0x168,0x36e /* ioports 0x168-0x16f,0x36e */ 82 83 The 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 90 Note that the first parameter reserves 8 contiguous ioports, whereas the 91 second value denotes a single ioport. If in doubt, do a 'cat /proc/ioports'. 92 93 In all probability the device uses these ports and IRQs if it is attached 94 to the appropriate ide channel. Pass the parameter for the correct ide 95 channel to the kernel, as explained above. 96 97 Any number of interfaces may share a single IRQ if necessary, at a slight 98 performance penalty, whether on separate cards or a single VLB card. 99 The IDE driver automatically detects and handles this. However, this may 100 or may not be harmful to your hardware.. two or more cards driving the same IRQ 101 can potentially burn each other's bus driver, though in practice this 102 seldom occurs. Be careful, and if in doubt, don't do it! 103 104 Drives are normally found by auto-probing and/or examining the CMOS/BIOS data. 105 For really weird situations, the apparent (fdisk) geometry can also be specified 106 on the kernel "command line" using LILO. The format of such lines is: 107 108 hdx=cyls,heads,sects 109 or hdx=cdrom 110 111 where 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 115 116 either {hda,hdb} or {hdc,hdd}. The results of successful auto-probing may 117 override the physical geometry/irq specified, though the "original" geometry 118 may be retained as the "logical" geometry for partitioning purposes (fdisk). 119 120 If the auto-probing during boot time confuses a drive (ie. the drive works 121 with hd.c but not with ide.c), then an command line option may be specified 122 for each drive for which you'd like the drive to skip the hardware 123 probe/identification sequence. For example: 124 125 hdb=noprobe 126 or 127 hdc=768,16,32 128 hdc=noprobe 129 130 Note that when only one IDE device is attached to an interface, it should be 131 jumpered as "single" or "master", *not* "slave". Many folks have had 132 "trouble" with cdroms because of this requirement, so the driver now probes 133 for both units, though success is more likely when the drive is jumpered 134 correctly. 135 136 Courtesy of Scott Snyder and others, the driver supports ATAPI cdrom drives 137 such as the NEC-260 and the new MITSUMI triple/quad speed drives. 138 Such drives will be identified at boot time, just like a hard disk. 139 140 If for some reason your cdrom drive is *not* found at boot time, you can force 141 the probe to look harder by supplying a kernel command line parameter 142 via LILO, such as: 143 144 hdc=cdrom /* hdc = "master" on second interface */ 145 or 146 hdd=cdrom /* hdd = "slave" on second interface */ 147 148 For example, a GW2000 system might have a hard drive on the primary 149 interface (/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 155 156 If, after doing all of the above, mount doesn't work and you see 157 errors from the driver (with dmesg) complaining about `status=0xff', 158 this means that the hardware is not responding to the driver's attempts 159 to 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. 173 174 If you always get timeout errors, interrupts from the drive are probably 175 not making it to the host. Check how you have the hardware jumpered 176 and make sure it matches what the driver expects (see the configuration 177 instructions above). If you have a PCI system, also check the BIOS 178 setup; I've had one report of a system which was shipped with IRQ 15 179 disabled by the BIOS. 180 181 The kernel is able to execute binaries directly off of the cdrom, 182 provided it is mounted with the default block size of 1024 (as above). 183 184 Please pass on any feedback on any of this stuff to the maintainer, 185 whose address can be found in linux/MAINTAINERS. 186 187 Note that if BOTH hd.c and ide.c are configured into the kernel, 188 hd.c will normally be allowed to control the primary IDE interface. 189 This is useful for older hardware that may be incompatible with ide.c, 190 and still allows newer hardware to run on the 2nd/3rd/4th IDE ports 191 under control of ide.c. To have ide.c also "take over" the primary 192 IDE port in this situation, use the "command line" parameter: ide0=0x1f0 193 194 The IDE driver is modularized. The high level disk/CD-ROM/tape/floppy 195 drivers can always be compiled as loadable modules, the chipset drivers 196 can only be compiled into the kernel, and the core code (ide.c) can be 197 compiled as a loadable module provided no chipset support is needed. 198 199 When using ide.c as a module in combination with kmod, add: 200 201 alias block-major-3 ide-probe 202 203 to /etc/modprobe.conf. 204 205 When ide.c is used as a module, you can pass command line parameters to the 206 driver 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 ================================================================================ 213 214 Summary of ide driver parameters for kernel command line 215 -------------------------------------------------------- 216 217 "hdx=" is recognized for all "x" from "a" to "u", such as "hdc". 218 219 "idex=" is recognized for all "x" from "0" to "9", 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=autotune" : driver will attempt to tune interface speed 232 to the fastest PIO mode supported, 233 if possible for this drive only. 234 Not fully supported by all chipset types, 235 and quite likely to cause trouble with 236 older/odd IDE drives. 237 238 "hdx=nodma" : disallow DMA 239 240 "idebus=xx" : inform IDE driver of VESA/PCI bus speed in MHz, 241 where "xx" is between 20 and 66 inclusive, 242 used when tuning chipset PIO modes. 243 For PCI bus, 25 is correct for a P75 system, 244 30 is correct for P90,P120,P180 systems, 245 and 33 is used for P100,P133,P166 systems. 246 If in doubt, use idebus=33 for PCI. 247 As for VLB, it is safest to not specify it. 248 Bigger values are safer than smaller ones. 249 250 "idex=base" : probe for an interface at the addr specified, 251 where "base" is usually 0x1f0 or 0x170 252 and "ctl" is assumed to be "base"+0x206 253 254 "idex=base,ctl" : specify both base and ctl 255 256 "idex=base,ctl,irq" : specify base, ctl, and irq number 257 258 "idex=serialize" : do not overlap operations on idex. Please note 259 that you will have to specify this option for 260 both the respective primary and secondary channel 261 to take effect. 262 263 "idex=four" : four drives on idex and ide(x^1) share same ports 264 265 "idex=reset" : reset interface after probe 266 267 "idex=ata66" : informs the interface that it has an 80c cable 268 for chipsets that are ATA-66 capable, but the 269 ability to bit test for detection is currently 270 unknown. 271 272 "ide=reverse" : formerly called to pci sub-system, but now local. 273 274 "ide=doubler" : probe/support IDE doublers on Amiga 275 276 There may be more options than shown -- use the source, Luke! 277 278 Everything else is rejected with a "BAD OPTION" message. 279 280 For legacy IDE VLB host drivers (ali14xx/dtc2278/ht6560b/qd65xx/umc8672) 281 you need to explicitly enable probing by using "probe" kernel parameter, 282 i.e. to enable probing for ALI M14xx chipsets (ali14xx host driver) use: 283 284 * "ali14xx.probe" boot option when ali14xx driver is built-in the kernel 285 286 * "probe" module parameter when ali14xx driver is compiled as module 287 ("modprobe ali14xx probe") 288 289 Also for legacy CMD640 host driver (cmd640) you need to use "probe_vlb" 290 kernel paremeter to enable probing for VLB version of the chipset (PCI ones 291 are detected automatically). 292 293 ================================================================================ 294 295 Some Terminology 296 ---------------- 297 IDE = Integrated Drive Electronics, meaning that each drive has a built-in 298 controller, which is why an "IDE interface card" is not a "controller card". 299 300 ATA = AT (the old IBM 286 computer) Attachment Interface, a draft American 301 National Standard for connecting hard drives to PCs. This is the official 302 name for "IDE". 303 304 The latest standards define some enhancements, known as the ATA-6 spec, 305 which grew out of vendor-specific "Enhanced IDE" (EIDE) implementations. 306 307 ATAPI = ATA Packet Interface, a new protocol for controlling the drives, 308 similar to SCSI protocols, created at the same time as the ATA2 standard. 309 ATAPI is currently used for controlling CDROM, TAPE and FLOPPY (ZIP or 310 LS120/240) devices, removable R/W cartridges, and for high capacity hard disk 311 drives. 312 313 mlord[AT]pobox[DOT]com 314 -- 315 316 Wed Apr 17 22:52:44 CEST 2002 edited by Marcin Dalecki, the current 317 maintainer. 318 319 Wed Aug 20 22:31:29 CEST 2003 updated ide boot options to current ide.c 320 comments at 2.6.0-test4 time. Maciej Soltysiak <solt[AT]dns.toxicfilms[DOT]tv>