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+
+ 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 "cmd640.probe_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).
+
+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:
+
+ ide_core.chs=[interface_number.device_number]:cyls,heads,sects
+or ide_core.cdrom=[interface_number.device_number]
+
+For example:
+
+ ide_core.chs=1.0:1050,32,64 ide_core.cdrom=1.1
+
+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:
+
+ ide_core.noprobe=0.1
+or
+ ide_core.chs=1.0:768,16,32
+ ide_core.noprobe=1.0
+
+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:
+
+ ide_core.cdrom=1.0 /* "master" on second interface (hdc) */
+or
+ ide_core.cdrom=1.1 /* "slave" on second interface (hdd) */
+
+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.
+
+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 a configuration file in /etc/modprobe.d/.
+
+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
+';'.
+
+
+================================================================================
+
+Summary of ide driver parameters for kernel command line
+--------------------------------------------------------
+
+For legacy IDE VLB host drivers (ali14xx/dtc2278/ht6560b/qd65xx/umc8672)
+you need to explicitly enable probing by using "probe" kernel parameter,
+i.e. to enable probing for ALI M14xx chipsets (ali14xx host driver) use:
+
+* "ali14xx.probe" boot option when ali14xx driver is built-in the kernel
+
+* "probe" module parameter when ali14xx driver is compiled as module
+ ("modprobe ali14xx probe")
+
+Also for legacy CMD640 host driver (cmd640) you need to use "probe_vlb"
+kernel paremeter to enable probing for VLB version of the chipset (PCI ones
+are detected automatically).
+
+You also need to use "probe" kernel parameter for ide-4drives driver
+(support for IDE generic chipset with four drives on one port).
+
+To enable support for IDE doublers on Amiga use "doubler" kernel parameter
+for gayle host driver (i.e. "gayle.doubler" if the driver is built-in).
+
+To force ignoring cable detection (this should be needed only if you're using
+short 40-wires cable which cannot be automatically detected - if this is not
+a case please report it as a bug instead) use "ignore_cable" kernel parameter:
+
+* "ide_core.ignore_cable=[interface_number]" boot option if IDE is built-in
+ (i.e. "ide_core.ignore_cable=1" to force ignoring cable for "ide1")
+
+* "ignore_cable=[interface_number]" module parameter (for ide_core module)
+ if IDE is compiled as module
+
+Other kernel parameters for ide_core are:
+
+* "nodma=[interface_number.device_number]" to disallow DMA for a device
+
+* "noflush=[interface_number.device_number]" to disable flush requests
+
+* "nohpa=[interface_number.device_number]" to disable Host Protected Area
+
+* "noprobe=[interface_number.device_number]" to skip probing
+
+* "nowerr=[interface_number.device_number]" to ignore the WRERR_STAT bit
+
+* "cdrom=[interface_number.device_number]" to force device as a CD-ROM
+
+* "chs=[interface_number.device_number]" to force device as a disk (using CHS)
+
+================================================================================
+
+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>