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diff --git a/Documentation/ide.txt b/Documentation/ide.txt new file mode 100644 index 00000000000..29866fbfb22 --- /dev/null +++ b/Documentation/ide.txt @@ -0,0 +1,394 @@ + + 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 respecitve 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 uptions to current ide.c +comments at 2.6.0-test4 time. Maciej Soltysiak <solt@dns.toxicfilms.tv> |