1============================================ 2Information regarding the Enhanced IDE drive 3============================================ 4 5 The hdparm utility can be used to control various IDE features on a 6 running system. It is packaged separately. Please Look for it on popular 7 linux FTP sites. 8 9------------------------------------------------------------------------------- 10 11.. important:: 12 13 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 39Common pitfalls 40=============== 41 42- 40-conductor IDE cables are capable of transferring data in DMA modes up to 43 udma2, but no faster. 44 45- If possible devices should be attached to separate channels if they are 46 available. Typically the disk on the first and CD-ROM on the second. 47 48- If you mix devices on the same cable, please consider using similar devices 49 in respect of the data transfer mode they support. 50 51- Even better try to stick to the same vendor and device type on the same 52 cable. 53 54This is the multiple IDE interface driver, as evolved from hd.c 55=============================================================== 56 57It supports up to 9 IDE interfaces per default, on one or more IRQs (usually 5814 & 15). There can be up to two drives per interface, as per the ATA-6 spec.:: 59 60 Primary: ide0, port 0x1f0; major=3; hda is minor=0; hdb is minor=64 61 Secondary: ide1, port 0x170; major=22; hdc is minor=0; hdd is minor=64 62 Tertiary: ide2, port 0x1e8; major=33; hde is minor=0; hdf is minor=64 63 Quaternary: ide3, port 0x168; major=34; hdg is minor=0; hdh is minor=64 64 fifth.. ide4, usually PCI, probed 65 sixth.. ide5, usually PCI, probed 66 67To access devices on interfaces > ide0, device entries please make sure that 68device files for them are present in /dev. If not, please create such 69entries, by using /dev/MAKEDEV. 70 71This driver automatically probes for most IDE interfaces (including all PCI 72ones), for the drives/geometries attached to those interfaces, and for the IRQ 73lines being used by the interfaces (normally 14, 15 for ide0/ide1). 74 75Any number of interfaces may share a single IRQ if necessary, at a slight 76performance penalty, whether on separate cards or a single VLB card. 77The IDE driver automatically detects and handles this. However, this may 78or may not be harmful to your hardware.. two or more cards driving the same IRQ 79can potentially burn each other's bus driver, though in practice this 80seldom occurs. Be careful, and if in doubt, don't do it! 81 82Drives are normally found by auto-probing and/or examining the CMOS/BIOS data. 83For really weird situations, the apparent (fdisk) geometry can also be specified 84on the kernel "command line" using LILO. The format of such lines is:: 85 86 ide_core.chs=[interface_number.device_number]:cyls,heads,sects 87 88or:: 89 90 ide_core.cdrom=[interface_number.device_number] 91 92For example:: 93 94 ide_core.chs=1.0:1050,32,64 ide_core.cdrom=1.1 95 96The results of successful auto-probing may override the physical geometry/irq 97specified, though the "original" geometry may be retained as the "logical" 98geometry for partitioning purposes (fdisk). 99 100If the auto-probing during boot time confuses a drive (ie. the drive works 101with hd.c but not with ide.c), then an command line option may be specified 102for each drive for which you'd like the drive to skip the hardware 103probe/identification sequence. For example:: 104 105 ide_core.noprobe=0.1 106 107or:: 108 109 ide_core.chs=1.0:768,16,32 110 ide_core.noprobe=1.0 111 112Note that when only one IDE device is attached to an interface, it should be 113jumpered as "single" or "master", *not* "slave". Many folks have had 114"trouble" with cdroms because of this requirement, so the driver now probes 115for both units, though success is more likely when the drive is jumpered 116correctly. 117 118Courtesy of Scott Snyder and others, the driver supports ATAPI cdrom drives 119such as the NEC-260 and the new MITSUMI triple/quad speed drives. 120Such drives will be identified at boot time, just like a hard disk. 121 122If for some reason your cdrom drive is *not* found at boot time, you can force 123the probe to look harder by supplying a kernel command line parameter 124via LILO, such as::: 125 126 ide_core.cdrom=1.0 /* "master" on second interface (hdc) */ 127 128or:: 129 130 ide_core.cdrom=1.1 /* "slave" on second interface (hdd) */ 131 132For example, a GW2000 system might have a hard drive on the primary 133interface (/dev/hda) and an IDE cdrom drive on the secondary interface 134(/dev/hdc). To mount a CD in the cdrom drive, one would use something like:: 135 136 ln -sf /dev/hdc /dev/cdrom 137 mkdir /mnt/cdrom 138 mount /dev/cdrom /mnt/cdrom -t iso9660 -o ro 139 140If, after doing all of the above, mount doesn't work and you see 141errors from the driver (with dmesg) complaining about `status=0xff`, 142this means that the hardware is not responding to the driver's attempts 143to read it. One of the following is probably the problem: 144 145 - Your hardware is broken. 146 147 - You are using the wrong address for the device, or you have the 148 drive jumpered wrong. Review the configuration instructions above. 149 150 - Your IDE controller requires some nonstandard initialization sequence 151 before it will work properly. If this is the case, there will often 152 be a separate MS-DOS driver just for the controller. IDE interfaces 153 on sound cards usually fall into this category. Such configurations 154 can often be made to work by first booting MS-DOS, loading the 155 appropriate drivers, and then warm-booting linux (without powering 156 off). This can be automated using loadlin in the MS-DOS autoexec. 157 158If you always get timeout errors, interrupts from the drive are probably 159not making it to the host. Check how you have the hardware jumpered 160and make sure it matches what the driver expects (see the configuration 161instructions above). If you have a PCI system, also check the BIOS 162setup; I've had one report of a system which was shipped with IRQ 15 163disabled by the BIOS. 164 165The kernel is able to execute binaries directly off of the cdrom, 166provided it is mounted with the default block size of 1024 (as above). 167 168Please pass on any feedback on any of this stuff to the maintainer, 169whose address can be found in linux/MAINTAINERS. 170 171The IDE driver is modularized. The high level disk/CD-ROM/tape/floppy 172drivers can always be compiled as loadable modules, the chipset drivers 173can only be compiled into the kernel, and the core code (ide.c) can be 174compiled as a loadable module provided no chipset support is needed. 175 176When using ide.c as a module in combination with kmod, add:: 177 178 alias block-major-3 ide-probe 179 180to a configuration file in /etc/modprobe.d/. 181 182When ide.c is used as a module, you can pass command line parameters to the 183driver using the "options=" keyword to insmod, while replacing any ',' with 184';'. 185 186 187Summary of ide driver parameters for kernel command line 188======================================================== 189 190For legacy IDE VLB host drivers (ali14xx/dtc2278/ht6560b/qd65xx/umc8672) 191you need to explicitly enable probing by using "probe" kernel parameter, 192i.e. to enable probing for ALI M14xx chipsets (ali14xx host driver) use: 193 194* "ali14xx.probe" boot option when ali14xx driver is built-in the kernel 195 196* "probe" module parameter when ali14xx driver is compiled as module 197 ("modprobe ali14xx probe") 198 199Also for legacy CMD640 host driver (cmd640) you need to use "probe_vlb" 200kernel paremeter to enable probing for VLB version of the chipset (PCI ones 201are detected automatically). 202 203You also need to use "probe" kernel parameter for ide-4drives driver 204(support for IDE generic chipset with four drives on one port). 205 206To enable support for IDE doublers on Amiga use "doubler" kernel parameter 207for gayle host driver (i.e. "gayle.doubler" if the driver is built-in). 208 209To force ignoring cable detection (this should be needed only if you're using 210short 40-wires cable which cannot be automatically detected - if this is not 211a case please report it as a bug instead) use "ignore_cable" kernel parameter: 212 213* "ide_core.ignore_cable=[interface_number]" boot option if IDE is built-in 214 (i.e. "ide_core.ignore_cable=1" to force ignoring cable for "ide1") 215 216* "ignore_cable=[interface_number]" module parameter (for ide_core module) 217 if IDE is compiled as module 218 219Other kernel parameters for ide_core are: 220 221* "nodma=[interface_number.device_number]" to disallow DMA for a device 222 223* "noflush=[interface_number.device_number]" to disable flush requests 224 225* "nohpa=[interface_number.device_number]" to disable Host Protected Area 226 227* "noprobe=[interface_number.device_number]" to skip probing 228 229* "nowerr=[interface_number.device_number]" to ignore the WRERR_STAT bit 230 231* "cdrom=[interface_number.device_number]" to force device as a CD-ROM 232 233* "chs=[interface_number.device_number]" to force device as a disk (using CHS) 234 235 236Some Terminology 237================ 238 239IDE 240 Integrated Drive Electronics, meaning that each drive has a built-in 241 controller, which is why an "IDE interface card" is not a "controller card". 242 243ATA 244 AT (the old IBM 286 computer) Attachment Interface, a draft American 245 National Standard for connecting hard drives to PCs. This is the official 246 name for "IDE". 247 248 The latest standards define some enhancements, known as the ATA-6 spec, 249 which grew out of vendor-specific "Enhanced IDE" (EIDE) implementations. 250 251ATAPI 252 ATA Packet Interface, a new protocol for controlling the drives, 253 similar to SCSI protocols, created at the same time as the ATA2 standard. 254 ATAPI is currently used for controlling CDROM, TAPE and FLOPPY (ZIP or 255 LS120/240) devices, removable R/W cartridges, and for high capacity hard disk 256 drives. 257 258mlord@pobox.com 259 260 261Wed Apr 17 22:52:44 CEST 2002 edited by Marcin Dalecki, the current 262maintainer. 263 264Wed Aug 20 22:31:29 CEST 2003 updated ide boot options to current ide.c 265comments at 2.6.0-test4 time. Maciej Soltysiak <solt@dns.toxicfilms.tv> 266