| Information regarding the Enhanced IDE drive in Linux 2.6 | |
| ============================================================================== | |
| The hdparm utility can be used to control various IDE features on a | |
| running system. It is packaged separately. Please Look for it on popular | |
| linux FTP sites. | |
| *** IMPORTANT NOTICES: BUGGY IDE CHIPSETS CAN CORRUPT DATA!! | |
| *** ================= | |
| *** PCI versions of the CMD640 and RZ1000 interfaces are now detected | |
| *** automatically at startup when PCI BIOS support is configured. | |
| *** | |
| *** Linux disables the "prefetch" ("readahead") mode of the RZ1000 | |
| *** to prevent data corruption possible due to hardware design flaws. | |
| *** | |
| *** For the CMD640, linux disables "IRQ unmasking" (hdparm -u1) on any | |
| *** drive for which the "prefetch" mode of the CMD640 is turned on. | |
| *** If "prefetch" is disabled (hdparm -p8), then "IRQ unmasking" can be | |
| *** used again. | |
| *** | |
| *** For the CMD640, linux disables "32bit I/O" (hdparm -c1) on any drive | |
| *** for which the "prefetch" mode of the CMD640 is turned off. | |
| *** If "prefetch" is enabled (hdparm -p9), then "32bit I/O" can be | |
| *** used again. | |
| *** | |
| *** The CMD640 is also used on some Vesa Local Bus (VLB) cards, and is *NOT* | |
| *** automatically detected by Linux. For safe, reliable operation with such | |
| *** interfaces, one *MUST* use the "ide0=cmd640_vlb" kernel option. | |
| *** | |
| *** Use of the "serialize" option is no longer necessary. | |
| ================================================================================ | |
| Common pitfalls: | |
| - 40-conductor IDE cables are capable of transferring data in DMA modes up to | |
| udma2, but no faster. | |
| - If possible devices should be attached to separate channels if they are | |
| available. Typically the disk on the first and CD-ROM on the second. | |
| - If you mix devices on the same cable, please consider using similar devices | |
| in respect of the data transfer mode they support. | |
| - Even better try to stick to the same vendor and device type on the same | |
| cable. | |
| ================================================================================ | |
| This is the multiple IDE interface driver, as evolved from hd.c. | |
| It supports up to 9 IDE interfaces per default, on one or more IRQs (usually | |
| 14 & 15). There can be up to two drives per interface, as per the ATA-6 spec. | |
| Primary: ide0, port 0x1f0; major=3; hda is minor=0; hdb is minor=64 | |
| Secondary: ide1, port 0x170; major=22; hdc is minor=0; hdd is minor=64 | |
| Tertiary: ide2, port 0x1e8; major=33; hde is minor=0; hdf is minor=64 | |
| Quaternary: ide3, port 0x168; major=34; hdg is minor=0; hdh is minor=64 | |
| fifth.. ide4, usually PCI, probed | |
| sixth.. ide5, usually PCI, probed | |
| To access devices on interfaces > ide0, device entries please make sure that | |
| device files for them are present in /dev. If not, please create such | |
| entries, by using /dev/MAKEDEV. | |
| This driver automatically probes for most IDE interfaces (including all PCI | |
| ones), for the drives/geometries attached to those interfaces, and for the IRQ | |
| lines being used by the interfaces (normally 14, 15 for ide0/ide1). | |
| For special cases, interfaces may be specified using kernel "command line" | |
| options. For example, | |
| ide3=0x168,0x36e,10 /* ioports 0x168-0x16f,0x36e, irq 10 */ | |
| Normally the irq number need not be specified, as ide.c will probe for it: | |
| ide3=0x168,0x36e /* ioports 0x168-0x16f,0x36e */ | |
| The standard port, and irq values are these: | |
| ide0=0x1f0,0x3f6,14 | |
| ide1=0x170,0x376,15 | |
| ide2=0x1e8,0x3ee,11 | |
| ide3=0x168,0x36e,10 | |
| Note that the first parameter reserves 8 contiguous ioports, whereas the | |
| second value denotes a single ioport. If in doubt, do a 'cat /proc/ioports'. | |
| In all probability the device uses these ports and IRQs if it is attached | |
| to the appropriate ide channel. Pass the parameter for the correct ide | |
| channel to the kernel, as explained above. | |
| Any number of interfaces may share a single IRQ if necessary, at a slight | |
| performance penalty, whether on separate cards or a single VLB card. | |
| The IDE driver automatically detects and handles this. However, this may | |
| or may not be harmful to your hardware.. two or more cards driving the same IRQ | |
| can potentially burn each other's bus driver, though in practice this | |
| seldom occurs. Be careful, and if in doubt, don't do it! | |
| Drives are normally found by auto-probing and/or examining the CMOS/BIOS data. | |
| For really weird situations, the apparent (fdisk) geometry can also be specified | |
| on the kernel "command line" using LILO. The format of such lines is: | |
| hdx=cyls,heads,sects,wpcom,irq | |
| or hdx=cdrom | |
| where hdx can be any of hda through hdh, Three values are required | |
| (cyls,heads,sects). For example: | |
| hdc=1050,32,64 hdd=cdrom | |
| either {hda,hdb} or {hdc,hdd}. The results of successful auto-probing may | |
| override the physical geometry/irq specified, though the "original" geometry | |
| may be retained as the "logical" geometry for partitioning purposes (fdisk). | |
| If the auto-probing during boot time confuses a drive (ie. the drive works | |
| with hd.c but not with ide.c), then an command line option may be specified | |
| for each drive for which you'd like the drive to skip the hardware | |
| probe/identification sequence. For example: | |
| hdb=noprobe | |
| or | |
| hdc=768,16,32 | |
| hdc=noprobe | |
| Note that when only one IDE device is attached to an interface, it should be | |
| jumpered as "single" or "master", *not* "slave". Many folks have had | |
| "trouble" with cdroms because of this requirement, so the driver now probes | |
| for both units, though success is more likely when the drive is jumpered | |
| correctly. | |
| Courtesy of Scott Snyder and others, the driver supports ATAPI cdrom drives | |
| such as the NEC-260 and the new MITSUMI triple/quad speed drives. | |
| Such drives will be identified at boot time, just like a hard disk. | |
| If for some reason your cdrom drive is *not* found at boot time, you can force | |
| the probe to look harder by supplying a kernel command line parameter | |
| via LILO, such as: | |
| hdc=cdrom /* hdc = "master" on second interface */ | |
| or | |
| hdd=cdrom /* hdd = "slave" on second interface */ | |
| For example, a GW2000 system might have a hard drive on the primary | |
| interface (/dev/hda) and an IDE cdrom drive on the secondary interface | |
| (/dev/hdc). To mount a CD in the cdrom drive, one would use something like: | |
| ln -sf /dev/hdc /dev/cdrom | |
| mkdir /mnt/cdrom | |
| mount /dev/cdrom /mnt/cdrom -t iso9660 -o ro | |
| If, after doing all of the above, mount doesn't work and you see | |
| errors from the driver (with dmesg) complaining about `status=0xff', | |
| this means that the hardware is not responding to the driver's attempts | |
| to read it. One of the following is probably the problem: | |
| - Your hardware is broken. | |
| - You are using the wrong address for the device, or you have the | |
| drive jumpered wrong. Review the configuration instructions above. | |
| - Your IDE controller requires some nonstandard initialization sequence | |
| before it will work properly. If this is the case, there will often | |
| be a separate MS-DOS driver just for the controller. IDE interfaces | |
| on sound cards usually fall into this category. Such configurations | |
| can often be made to work by first booting MS-DOS, loading the | |
| appropriate drivers, and then warm-booting linux (without powering | |
| off). This can be automated using loadlin in the MS-DOS autoexec. | |
| If you always get timeout errors, interrupts from the drive are probably | |
| not making it to the host. Check how you have the hardware jumpered | |
| and make sure it matches what the driver expects (see the configuration | |
| instructions above). If you have a PCI system, also check the BIOS | |
| setup; I've had one report of a system which was shipped with IRQ 15 | |
| disabled by the BIOS. | |
| The kernel is able to execute binaries directly off of the cdrom, | |
| provided it is mounted with the default block size of 1024 (as above). | |
| Please pass on any feedback on any of this stuff to the maintainer, | |
| whose address can be found in linux/MAINTAINERS. | |
| Note that if BOTH hd.c and ide.c are configured into the kernel, | |
| hd.c will normally be allowed to control the primary IDE interface. | |
| This is useful for older hardware that may be incompatible with ide.c, | |
| and still allows newer hardware to run on the 2nd/3rd/4th IDE ports | |
| under control of ide.c. To have ide.c also "take over" the primary | |
| IDE port in this situation, use the "command line" parameter: ide0=0x1f0 | |
| The IDE driver is modularized. The high level disk/CD-ROM/tape/floppy | |
| drivers can always be compiled as loadable modules, the chipset drivers | |
| can only be compiled into the kernel, and the core code (ide.c) can be | |
| compiled as a loadable module provided no chipset support is needed. | |
| When using ide.c as a module in combination with kmod, add: | |
| alias block-major-3 ide-probe | |
| to /etc/modprobe.conf. | |
| When ide.c is used as a module, you can pass command line parameters to the | |
| driver using the "options=" keyword to insmod, while replacing any ',' with | |
| ';'. For example: | |
| insmod ide.o options="ide0=serialize ide1=serialize ide2=0x1e8;0x3ee;11" | |
| ================================================================================ | |
| Summary of ide driver parameters for kernel command line | |
| -------------------------------------------------------- | |
| "hdx=" is recognized for all "x" from "a" to "h", such as "hdc". | |
| "idex=" is recognized for all "x" from "0" to "3", such as "ide1". | |
| "hdx=noprobe" : drive may be present, but do not probe for it | |
| "hdx=none" : drive is NOT present, ignore cmos and do not probe | |
| "hdx=nowerr" : ignore the WRERR_STAT bit on this drive | |
| "hdx=cdrom" : drive is present, and is a cdrom drive | |
| "hdx=cyl,head,sect" : disk drive is present, with specified geometry | |
| "hdx=remap" : remap access of sector 0 to sector 1 (for EZDrive) | |
| "hdx=remap63" : remap the drive: add 63 to all sector numbers | |
| (for DM OnTrack) | |
| "hdx=autotune" : driver will attempt to tune interface speed | |
| to the fastest PIO mode supported, | |
| if possible for this drive only. | |
| Not fully supported by all chipset types, | |
| and quite likely to cause trouble with | |
| older/odd IDE drives. | |
| "hdx=swapdata" : when the drive is a disk, byte swap all data | |
| "hdx=bswap" : same as above.......... | |
| "hdx=scsi" : the return of the ide-scsi flag, this is useful for | |
| allowing ide-floppy, ide-tape, and ide-cdrom|writers | |
| to use ide-scsi emulation on a device specific option. | |
| "idebus=xx" : inform IDE driver of VESA/PCI bus speed in MHz, | |
| where "xx" is between 20 and 66 inclusive, | |
| used when tuning chipset PIO modes. | |
| For PCI bus, 25 is correct for a P75 system, | |
| 30 is correct for P90,P120,P180 systems, | |
| and 33 is used for P100,P133,P166 systems. | |
| If in doubt, use idebus=33 for PCI. | |
| As for VLB, it is safest to not specify it. | |
| Bigger values are safer than smaller ones. | |
| "idex=noprobe" : do not attempt to access/use this interface | |
| "idex=base" : probe for an interface at the addr specified, | |
| where "base" is usually 0x1f0 or 0x170 | |
| and "ctl" is assumed to be "base"+0x206 | |
| "idex=base,ctl" : specify both base and ctl | |
| "idex=base,ctl,irq" : specify base, ctl, and irq number | |
| "idex=autotune" : driver will attempt to tune interface speed | |
| to the fastest PIO mode supported, | |
| for all drives on this interface. | |
| Not fully supported by all chipset types, | |
| and quite likely to cause trouble with | |
| older/odd IDE drives. | |
| "idex=noautotune" : driver will NOT attempt to tune interface speed | |
| This is the default for most chipsets, | |
| except the cmd640. | |
| "idex=serialize" : do not overlap operations on idex. Please note | |
| that you will have to specify this option for | |
| both the respective primary and secondary channel | |
| to take effect. | |
| "idex=four" : four drives on idex and ide(x^1) share same ports | |
| "idex=reset" : reset interface after probe | |
| "idex=dma" : automatically configure/use DMA if possible. | |
| "idex=ata66" : informs the interface that it has an 80c cable | |
| for chipsets that are ATA-66 capable, but the | |
| ability to bit test for detection is currently | |
| unknown. | |
| "ide=reverse" : formerly called to pci sub-system, but now local. | |
| "ide=nodma" : disable DMA globally for the IDE subsystem. | |
| The following are valid ONLY on ide0, which usually corresponds | |
| to the first ATA interface found on the particular host, and the defaults for | |
| the base,ctl ports must not be altered. | |
| "ide0=dtc2278" : probe/support DTC2278 interface | |
| "ide0=ht6560b" : probe/support HT6560B interface | |
| "ide0=cmd640_vlb" : *REQUIRED* for VLB cards with the CMD640 chip | |
| (not for PCI -- automatically detected) | |
| "ide0=qd65xx" : probe/support qd65xx interface | |
| "ide0=ali14xx" : probe/support ali14xx chipsets (ALI M1439/M1443/M1445) | |
| "ide0=umc8672" : probe/support umc8672 chipsets | |
| "ide=doubler" : probe/support IDE doublers on Amiga | |
| There may be more options than shown -- use the source, Luke! | |
| Everything else is rejected with a "BAD OPTION" message. | |
| ================================================================================ | |
| IDE ATAPI streaming tape driver | |
| ------------------------------- | |
| This driver is a part of the Linux ide driver and works in co-operation | |
| with linux/drivers/block/ide.c. | |
| The driver, in co-operation with ide.c, basically traverses the | |
| request-list for the block device interface. The character device | |
| interface, on the other hand, creates new requests, adds them | |
| to the request-list of the block device, and waits for their completion. | |
| Pipelined operation mode is now supported on both reads and writes. | |
| The block device major and minor numbers are determined from the | |
| tape's relative position in the ide interfaces, as explained in ide.c. | |
| The character device interface consists of the following devices: | |
| ht0 major 37, minor 0 first IDE tape, rewind on close. | |
| ht1 major 37, minor 1 second IDE tape, rewind on close. | |
| ... | |
| nht0 major 37, minor 128 first IDE tape, no rewind on close. | |
| nht1 major 37, minor 129 second IDE tape, no rewind on close. | |
| ... | |
| Run /dev/MAKEDEV to create the above entries. | |
| The general magnetic tape commands compatible interface, as defined by | |
| include/linux/mtio.h, is accessible through the character device. | |
| General ide driver configuration options, such as the interrupt-unmask | |
| flag, can be configured by issuing an ioctl to the block device interface, | |
| as any other ide device. | |
| Our own ide-tape ioctl's can be issued to either the block device or | |
| the character device interface. | |
| Maximal throughput with minimal bus load will usually be achieved in the | |
| following scenario: | |
| 1. ide-tape is operating in the pipelined operation mode. | |
| 2. No buffering is performed by the user backup program. | |
| ================================================================================ | |
| Some Terminology | |
| ---------------- | |
| IDE = Integrated Drive Electronics, meaning that each drive has a built-in | |
| controller, which is why an "IDE interface card" is not a "controller card". | |
| ATA = AT (the old IBM 286 computer) Attachment Interface, a draft American | |
| National Standard for connecting hard drives to PCs. This is the official | |
| name for "IDE". | |
| The latest standards define some enhancements, known as the ATA-6 spec, | |
| which grew out of vendor-specific "Enhanced IDE" (EIDE) implementations. | |
| ATAPI = ATA Packet Interface, a new protocol for controlling the drives, | |
| similar to SCSI protocols, created at the same time as the ATA2 standard. | |
| ATAPI is currently used for controlling CDROM, TAPE and FLOPPY (ZIP or | |
| LS120/240) devices, removable R/W cartridges, and for high capacity hard disk | |
| drives. | |
| mlord@pobox.com | |
| -- | |
| Wed Apr 17 22:52:44 CEST 2002 edited by Marcin Dalecki, the current | |
| maintainer. | |
| Wed Aug 20 22:31:29 CEST 2003 updated ide boot options to current ide.c | |
| comments at 2.6.0-test4 time. Maciej Soltysiak <solt@dns.toxicfilms.tv> |