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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 "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>