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================================================================================ 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 74Any number of interfaces may share a single IRQ if necessary, at a slight 75performance penalty, whether on separate cards or a single VLB card. 76The IDE driver automatically detects and handles this. However, this may 77or may not be harmful to your hardware.. two or more cards driving the same IRQ 78can potentially burn each other's bus driver, though in practice this 79seldom occurs. Be careful, and if in doubt, don't do it! 80 81Drives are normally found by auto-probing and/or examining the CMOS/BIOS data. 82For really weird situations, the apparent (fdisk) geometry can also be specified 83on the kernel "command line" using LILO. The format of such lines is: 84 85 ide_core.chs=[interface_number.device_number]:cyls,heads,sects 86or ide_core.cdrom=[interface_number.device_number] 87 88For example: 89 90 ide_core.chs=1.0:1050,32,64 ide_core.cdrom=1.1 91 92The results of successful auto-probing may override the physical geometry/irq 93specified, though the "original" geometry may be retained as the "logical" 94geometry for partitioning purposes (fdisk). 95 96If the auto-probing during boot time confuses a drive (ie. the drive works 97with hd.c but not with ide.c), then an command line option may be specified 98for each drive for which you'd like the drive to skip the hardware 99probe/identification sequence. For example: 100 101 ide_core.noprobe=0.1 102or 103 ide_core.chs=1.0:768,16,32 104 ide_core.noprobe=1.0 105 106Note that when only one IDE device is attached to an interface, it should be 107jumpered as "single" or "master", *not* "slave". Many folks have had 108"trouble" with cdroms because of this requirement, so the driver now probes 109for both units, though success is more likely when the drive is jumpered 110correctly. 111 112Courtesy of Scott Snyder and others, the driver supports ATAPI cdrom drives 113such as the NEC-260 and the new MITSUMI triple/quad speed drives. 114Such drives will be identified at boot time, just like a hard disk. 115 116If for some reason your cdrom drive is *not* found at boot time, you can force 117the probe to look harder by supplying a kernel command line parameter 118via LILO, such as: 119 120 ide_core.cdrom=1.0 /* "master" on second interface (hdc) */ 121or 122 ide_core.cdrom=1.1 /* "slave" on second interface (hdd) */ 123 124For example, a GW2000 system might have a hard drive on the primary 125interface (/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 132If, after doing all of the above, mount doesn't work and you see 133errors from the driver (with dmesg) complaining about `status=0xff', 134this means that the hardware is not responding to the driver's attempts 135to 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 150If you always get timeout errors, interrupts from the drive are probably 151not making it to the host. Check how you have the hardware jumpered 152and make sure it matches what the driver expects (see the configuration 153instructions above). If you have a PCI system, also check the BIOS 154setup; I've had one report of a system which was shipped with IRQ 15 155disabled by the BIOS. 156 157The kernel is able to execute binaries directly off of the cdrom, 158provided it is mounted with the default block size of 1024 (as above). 159 160Please pass on any feedback on any of this stuff to the maintainer, 161whose address can be found in linux/MAINTAINERS. 162 163The IDE driver is modularized. The high level disk/CD-ROM/tape/floppy 164drivers can always be compiled as loadable modules, the chipset drivers 165can only be compiled into the kernel, and the core code (ide.c) can be 166compiled as a loadable module provided no chipset support is needed. 167 168When using ide.c as a module in combination with kmod, add: 169 170 alias block-major-3 ide-probe 171 172to a configuration file in /etc/modprobe.d/. 173 174When ide.c is used as a module, you can pass command line parameters to the 175driver using the "options=" keyword to insmod, while replacing any ',' with 176';'. 177 178 179================================================================================ 180 181Summary of ide driver parameters for kernel command line 182-------------------------------------------------------- 183 184For legacy IDE VLB host drivers (ali14xx/dtc2278/ht6560b/qd65xx/umc8672) 185you need to explicitly enable probing by using "probe" kernel parameter, 186i.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 193Also for legacy CMD640 host driver (cmd640) you need to use "probe_vlb" 194kernel paremeter to enable probing for VLB version of the chipset (PCI ones 195are detected automatically). 196 197You also need to use "probe" kernel parameter for ide-4drives driver 198(support for IDE generic chipset with four drives on one port). 199 200To enable support for IDE doublers on Amiga use "doubler" kernel parameter 201for gayle host driver (i.e. "gayle.doubler" if the driver is built-in). 202 203To force ignoring cable detection (this should be needed only if you're using 204short 40-wires cable which cannot be automatically detected - if this is not 205a 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 213Other 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 231Some Terminology 232---------------- 233IDE = Integrated Drive Electronics, meaning that each drive has a built-in 234controller, which is why an "IDE interface card" is not a "controller card". 235 236ATA = AT (the old IBM 286 computer) Attachment Interface, a draft American 237National Standard for connecting hard drives to PCs. This is the official 238name for "IDE". 239 240The latest standards define some enhancements, known as the ATA-6 spec, 241which grew out of vendor-specific "Enhanced IDE" (EIDE) implementations. 242 243ATAPI = ATA Packet Interface, a new protocol for controlling the drives, 244similar to SCSI protocols, created at the same time as the ATA2 standard. 245ATAPI is currently used for controlling CDROM, TAPE and FLOPPY (ZIP or 246LS120/240) devices, removable R/W cartridges, and for high capacity hard disk 247drives. 248 249mlord@pobox.com 250-- 251 252Wed Apr 17 22:52:44 CEST 2002 edited by Marcin Dalecki, the current 253maintainer. 254 255Wed Aug 20 22:31:29 CEST 2003 updated ide boot options to current ide.c 256comments at 2.6.0-test4 time. Maciej Soltysiak <solt@dns.toxicfilms.tv> 257