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+                Summary of CDROM ioctl calls.
+                ============================
+
+                Edward A. Falk <efalk@google.com>
+
+                November, 2004
+
+This document attempts to describe the ioctl(2) calls supported by
+the CDROM layer.  These are by-and-large implemented (as of Linux 2.6)
+in drivers/cdrom/cdrom.c and drivers/block/scsi_ioctl.c
+
+ioctl values are listed in <linux/cdrom.h>.  As of this writing, they
+are as follows:
+
+        CDROMPAUSE              Pause Audio Operation
+        CDROMRESUME             Resume paused Audio Operation
+        CDROMPLAYMSF            Play Audio MSF (struct cdrom_msf)
+        CDROMPLAYTRKIND         Play Audio Track/index (struct cdrom_ti)
+        CDROMREADTOCHDR         Read TOC header (struct cdrom_tochdr)
+        CDROMREADTOCENTRY       Read TOC entry (struct cdrom_tocentry)
+        CDROMSTOP               Stop the cdrom drive
+        CDROMSTART              Start the cdrom drive
+        CDROMEJECT              Ejects the cdrom media
+        CDROMVOLCTRL            Control output volume (struct cdrom_volctrl)
+        CDROMSUBCHNL            Read subchannel data (struct cdrom_subchnl)
+        CDROMREADMODE2          Read CDROM mode 2 data (2336 Bytes)
+                                           (struct cdrom_read)
+        CDROMREADMODE1          Read CDROM mode 1 data (2048 Bytes)
+                                           (struct cdrom_read)
+        CDROMREADAUDIO          (struct cdrom_read_audio)
+        CDROMEJECT_SW           enable(1)/disable(0) auto-ejecting
+        CDROMMULTISESSION       Obtain the start-of-last-session
+                                  address of multi session disks
+                                  (struct cdrom_multisession)
+        CDROM_GET_MCN           Obtain the "Universal Product Code"
+                                   if available (struct cdrom_mcn)
+        CDROM_GET_UPC           Deprecated, use CDROM_GET_MCN instead.
+        CDROMRESET              hard-reset the drive
+        CDROMVOLREAD            Get the drive's volume setting
+                                          (struct cdrom_volctrl)
+        CDROMREADRAW            read data in raw mode (2352 Bytes)
+                                           (struct cdrom_read)
+        CDROMREADCOOKED         read data in cooked mode
+        CDROMSEEK               seek msf address
+        CDROMPLAYBLK            scsi-cd only, (struct cdrom_blk)
+        CDROMREADALL            read all 2646 bytes
+        CDROMGETSPINDOWN        return 4-bit spindown value
+        CDROMSETSPINDOWN        set 4-bit spindown value
+        CDROMCLOSETRAY          pendant of CDROMEJECT
+        CDROM_SET_OPTIONS       Set behavior options
+        CDROM_CLEAR_OPTIONS     Clear behavior options
+        CDROM_SELECT_SPEED      Set the CD-ROM speed
+        CDROM_SELECT_DISC       Select disc (for juke-boxes)
+        CDROM_MEDIA_CHANGED     Check is media changed
+        CDROM_DRIVE_STATUS      Get tray position, etc.
+        CDROM_DISC_STATUS       Get disc type, etc.
+        CDROM_CHANGER_NSLOTS    Get number of slots
+        CDROM_LOCKDOOR          lock or unlock door
+        CDROM_DEBUG             Turn debug messages on/off
+        CDROM_GET_CAPABILITY    get capabilities
+        CDROMAUDIOBUFSIZ        set the audio buffer size
+        DVD_READ_STRUCT         Read structure
+        DVD_WRITE_STRUCT        Write structure
+        DVD_AUTH                Authentication
+        CDROM_SEND_PACKET       send a packet to the drive
+        CDROM_NEXT_WRITABLE     get next writable block
+        CDROM_LAST_WRITTEN      get last block written on disc
+
+
+The information that follows was determined from reading kernel source
+code.  It is likely that some corrections will be made over time.
+
+
+
+
+
+
+
+General:
+
+        Unless otherwise specified, all ioctl calls return 0 on success
+        and -1 with errno set to an appropriate value on error.  (Some
+        ioctls return non-negative data values.)
+
+        Unless otherwise specified, all ioctl calls return -1 and set
+        errno to EFAULT on a failed attempt to copy data to or from user
+        address space.
+
+        Individual drivers may return error codes not listed here.
+
+        Unless otherwise specified, all data structures and constants
+        are defined in <linux/cdrom.h>
+
+
+
+
+CDROMPAUSE                      Pause Audio Operation
+
+        usage:
+
+          ioctl(fd, CDROMPAUSE, 0);
+
+        inputs:         none
+
+        outputs:        none
+
+        error return:
+          ENOSYS        cd drive not audio-capable.
+
+
+CDROMRESUME                     Resume paused Audio Operation
+
+        usage:
+
+          ioctl(fd, CDROMRESUME, 0);
+
+        inputs:         none
+
+        outputs:        none
+
+        error return:
+          ENOSYS        cd drive not audio-capable.
+
+
+CDROMPLAYMSF                    Play Audio MSF (struct cdrom_msf)
+
+        usage:
+
+          struct cdrom_msf msf;
+          ioctl(fd, CDROMPLAYMSF, &msf);
+
+        inputs:
+          cdrom_msf structure, describing a segment of music to play
+
+        outputs:        none
+
+        error return:
+          ENOSYS        cd drive not audio-capable.
+
+        notes:
+          MSF stands for minutes-seconds-frames
+          LBA stands for logical block address
+
+          Segment is described as start and end times, where each time
+          is described as minutes:seconds:frames.  A frame is 1/75 of
+          a second.
+
+
+CDROMPLAYTRKIND                 Play Audio Track/index (struct cdrom_ti)
+
+        usage:
+
+          struct cdrom_ti ti;
+          ioctl(fd, CDROMPLAYTRKIND, &ti);
+
+        inputs:
+          cdrom_ti structure, describing a segment of music to play
+
+        outputs:        none
+
+        error return:
+          ENOSYS        cd drive not audio-capable.
+
+        notes:
+          Segment is described as start and end times, where each time
+          is described as a track and an index.
+
+
+
+CDROMREADTOCHDR                 Read TOC header (struct cdrom_tochdr)
+
+        usage:
+
+          cdrom_tochdr header;
+          ioctl(fd, CDROMREADTOCHDR, &header);
+
+        inputs:
+          cdrom_tochdr structure
+
+        outputs:
+          cdrom_tochdr structure
+
+        error return:
+          ENOSYS        cd drive not audio-capable.
+
+
+
+CDROMREADTOCENTRY               Read TOC entry (struct cdrom_tocentry)
+
+        usage:
+
+          struct cdrom_tocentry entry;
+          ioctl(fd, CDROMREADTOCENTRY, &entry);
+
+        inputs:
+          cdrom_tocentry structure
+
+        outputs:
+          cdrom_tocentry structure
+
+        error return:
+          ENOSYS        cd drive not audio-capable.
+          EINVAL        entry.cdte_format not CDROM_MSF or CDROM_LBA
+          EINVAL        requested track out of bounds
+          EIO           I/O error reading TOC
+
+        notes:
+          TOC stands for Table Of Contents
+          MSF stands for minutes-seconds-frames
+          LBA stands for logical block address
+
+
+
+CDROMSTOP                       Stop the cdrom drive
+
+        usage:
+
+          ioctl(fd, CDROMSTOP, 0);
+
+        inputs:         none
+
+        outputs:        none
+
+        error return:
+          ENOSYS        cd drive not audio-capable.
+
+        notes:
+          Exact interpretation of this ioctl depends on the device,
+          but most seem to spin the drive down.
+
+
+CDROMSTART                      Start the cdrom drive
+
+        usage:
+
+          ioctl(fd, CDROMSTART, 0);
+
+        inputs:         none
+
+        outputs:        none
+
+        error return:
+          ENOSYS        cd drive not audio-capable.
+
+        notes:
+          Exact interpretation of this ioctl depends on the device,
+          but most seem to spin the drive up and/or close the tray.
+          Other devices ignore the ioctl completely.
+
+
+CDROMEJECT                      Ejects the cdrom media
+
+        usage:
+
+          ioctl(fd, CDROMEJECT, 0);
+
+        inputs:         none
+
+        outputs:        none
+
+        error returns:
+          ENOSYS        cd drive not capable of ejecting
+          EBUSY         other processes are accessing drive, or door is locked
+
+        notes:
+          See CDROM_LOCKDOOR, below.
+
+
+
+CDROMCLOSETRAY                  pendant of CDROMEJECT
+
+        usage:
+
+          ioctl(fd, CDROMEJECT, 0);
+
+        inputs:         none
+
+        outputs:        none
+
+        error returns:
+          ENOSYS        cd drive not capable of ejecting
+          EBUSY         other processes are accessing drive, or door is locked
+
+        notes:
+          See CDROM_LOCKDOOR, below.
+
+
+
+CDROMVOLCTRL                    Control output volume (struct cdrom_volctrl)
+
+        usage:
+
+          struct cdrom_volctrl volume;
+          ioctl(fd, CDROMVOLCTRL, &volume);
+
+        inputs:
+          cdrom_volctrl structure containing volumes for up to 4
+          channels.
+
+        outputs:        none
+
+        error return:
+          ENOSYS        cd drive not audio-capable.
+
+
+
+CDROMVOLREAD                    Get the drive's volume setting
+                                          (struct cdrom_volctrl)
+
+        usage:
+
+          struct cdrom_volctrl volume;
+          ioctl(fd, CDROMVOLREAD, &volume);
+
+        inputs:         none
+
+        outputs:
+          The current volume settings.
+
+        error return:
+          ENOSYS        cd drive not audio-capable.
+
+
+
+CDROMSUBCHNL                    Read subchannel data (struct cdrom_subchnl)
+
+        usage:
+
+          struct cdrom_subchnl q;
+          ioctl(fd, CDROMSUBCHNL, &q);
+
+        inputs:
+          cdrom_subchnl structure
+
+        outputs:
+          cdrom_subchnl structure
+
+        error return:
+          ENOSYS        cd drive not audio-capable.
+          EINVAL        format not CDROM_MSF or CDROM_LBA
+
+        notes:
+          Format is converted to CDROM_MSF on return
+
+
+
+CDROMREADRAW                    read data in raw mode (2352 Bytes)
+                                           (struct cdrom_read)
+
+        usage:
+
+          union {
+            struct cdrom_msf msf;               /* input */
+            char buffer[CD_FRAMESIZE_RAW];      /* return */
+          } arg;
+          ioctl(fd, CDROMREADRAW, &arg);
+
+        inputs:
+          cdrom_msf structure indicating an address to read.
+          Only the start values are significant.
+
+        outputs:
+          Data written to address provided by user.
+
+        error return:
+          EINVAL        address less than 0, or msf less than 0:2:0
+          ENOMEM        out of memory
+
+        notes:
+          As of 2.6.8.1, comments in <linux/cdrom.h> indicate that this
+          ioctl accepts a cdrom_read structure, but actual source code
+          reads a cdrom_msf structure and writes a buffer of data to
+          the same address.
+
+          MSF values are converted to LBA values via this formula:
+
+            lba = (((m * CD_SECS) + s) * CD_FRAMES + f) - CD_MSF_OFFSET;
+
+
+
+
+CDROMREADMODE1                  Read CDROM mode 1 data (2048 Bytes)
+                                           (struct cdrom_read)
+
+        notes:
+          Identical to CDROMREADRAW except that block size is
+          CD_FRAMESIZE (2048) bytes
+
+
+
+CDROMREADMODE2                  Read CDROM mode 2 data (2336 Bytes)
+                                           (struct cdrom_read)
+
+        notes:
+          Identical to CDROMREADRAW except that block size is
+          CD_FRAMESIZE_RAW0 (2336) bytes
+
+
+
+CDROMREADAUDIO                  (struct cdrom_read_audio)
+
+        usage:
+
+          struct cdrom_read_audio ra;
+          ioctl(fd, CDROMREADAUDIO, &ra);
+
+        inputs:
+          cdrom_read_audio structure containing read start
+          point and length
+
+        outputs:
+          audio data, returned to buffer indicated by ra
+
+        error return:
+          EINVAL        format not CDROM_MSF or CDROM_LBA
+          EINVAL        nframes not in range [1 75]
+          ENXIO         drive has no queue (probably means invalid fd)
+          ENOMEM        out of memory
+
+
+CDROMEJECT_SW                   enable(1)/disable(0) auto-ejecting
+
+        usage:
+
+          int val;
+          ioctl(fd, CDROMEJECT_SW, val);
+
+        inputs:
+          Flag specifying auto-eject flag.
+
+        outputs:        none
+
+        error return:
+          ENOSYS        Drive is not capable of ejecting.
+          EBUSY         Door is locked
+
+
+
+
+CDROMMULTISESSION               Obtain the start-of-last-session
+                                  address of multi session disks
+                                  (struct cdrom_multisession)
+        usage:
+
+          struct cdrom_multisession ms_info;
+          ioctl(fd, CDROMMULTISESSION, &ms_info);
+
+        inputs:
+          cdrom_multisession structure containing desired
+          format.
+
+        outputs:
+          cdrom_multisession structure is filled with last_session
+          information.
+
+        error return:
+          EINVAL        format not CDROM_MSF or CDROM_LBA
+
+
+CDROM_GET_MCN                   Obtain the "Universal Product Code"
+                                   if available (struct cdrom_mcn)
+
+        usage:
+
+          struct cdrom_mcn mcn;
+          ioctl(fd, CDROM_GET_MCN, &mcn);
+
+        inputs:         none
+
+        outputs:
+          Universal Product Code
+
+        error return:
+          ENOSYS        Drive is not capable of reading MCN data.
+
+        notes:
+          Source code comments state:
+
+            The following function is implemented, although very few
+            audio discs give Universal Product Code information, which
+            should just be the Medium Catalog Number on the box.  Note,
+            that the way the code is written on the CD is /not/ uniform
+            across all discs!
+
+
+
+
+CDROM_GET_UPC                   CDROM_GET_MCN  (deprecated)
+
+        Not implemented, as of 2.6.8.1
+
+
+
+CDROMRESET                      hard-reset the drive
+
+        usage:
+
+          ioctl(fd, CDROMRESET, 0);
+
+        inputs:         none
+
+        outputs:        none
+
+        error return:
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          ENOSYS        Drive is not capable of resetting.
+
+
+
+
+CDROMREADCOOKED                 read data in cooked mode
+
+        usage:
+
+          u8 buffer[CD_FRAMESIZE]
+          ioctl(fd, CDROMREADCOOKED, buffer);
+
+        inputs:         none
+
+        outputs:
+          2048 bytes of data, "cooked" mode.
+
+        notes:
+          Not implemented on all drives.
+
+
+
+
+CDROMREADALL                    read all 2646 bytes
+
+        Same as CDROMREADCOOKED, but reads 2646 bytes.
+
+
+
+CDROMSEEK                       seek msf address
+
+        usage:
+
+          struct cdrom_msf msf;
+          ioctl(fd, CDROMSEEK, &msf);
+
+        inputs:
+          MSF address to seek to.
+
+        outputs:        none
+
+
+
+CDROMPLAYBLK                    scsi-cd only, (struct cdrom_blk)
+
+        usage:
+
+          struct cdrom_blk blk;
+          ioctl(fd, CDROMPLAYBLK, &blk);
+
+        inputs:
+          Region to play
+
+        outputs:        none
+
+
+
+CDROMGETSPINDOWN
+
+        usage:
+
+          char spindown;
+          ioctl(fd, CDROMGETSPINDOWN, &spindown);
+
+        inputs:         none
+
+        outputs:
+          The value of the current 4-bit spindown value.
+
+
+
+
+CDROMSETSPINDOWN
+
+        usage:
+
+          char spindown
+          ioctl(fd, CDROMSETSPINDOWN, &spindown);
+
+        inputs:
+          4-bit value used to control spindown (TODO: more detail here)
+
+        outputs:        none
+
+
+
+
+
+CDROM_SET_OPTIONS               Set behavior options
+
+        usage:
+
+          int options;
+          ioctl(fd, CDROM_SET_OPTIONS, options);
+
+        inputs:
+          New values for drive options.  The logical 'or' of:
+            CDO_AUTO_CLOSE      close tray on first open(2)
+            CDO_AUTO_EJECT      open tray on last release
+            CDO_USE_FFLAGS      use O_NONBLOCK information on open
+            CDO_LOCK            lock tray on open files
+            CDO_CHECK_TYPE      check type on open for data
+
+        outputs:
+          Returns the resulting options settings in the
+          ioctl return value.  Returns -1 on error.
+
+        error return:
+          ENOSYS        selected option(s) not supported by drive.
+
+
+
+
+CDROM_CLEAR_OPTIONS             Clear behavior options
+
+        Same as CDROM_SET_OPTIONS, except that selected options are
+        turned off.
+
+
+
+CDROM_SELECT_SPEED              Set the CD-ROM speed
+
+        usage:
+
+          int speed;
+          ioctl(fd, CDROM_SELECT_SPEED, speed);
+
+        inputs:
+          New drive speed.
+
+        outputs:        none
+
+        error return:
+          ENOSYS        speed selection not supported by drive.
+
+
+
+CDROM_SELECT_DISC               Select disc (for juke-boxes)
+
+        usage:
+
+          int disk;
+          ioctl(fd, CDROM_SELECT_DISC, disk);
+
+        inputs:
+          Disk to load into drive.
+
+        outputs:        none
+
+        error return:
+          EINVAL        Disk number beyond capacity of drive
+
+
+
+CDROM_MEDIA_CHANGED             Check is media changed
+
+        usage:
+
+          int slot;
+          ioctl(fd, CDROM_MEDIA_CHANGED, slot);
+
+        inputs:
+          Slot number to be tested, always zero except for jukeboxes.
+          May also be special values CDSL_NONE or CDSL_CURRENT
+
+        outputs:
+          Ioctl return value is 0 or 1 depending on whether the media
+          has been changed, or -1 on error.
+
+        error returns:
+          ENOSYS        Drive can't detect media change
+          EINVAL        Slot number beyond capacity of drive
+          ENOMEM        Out of memory
+
+
+
+CDROM_DRIVE_STATUS              Get tray position, etc.
+
+        usage:
+
+          int slot;
+          ioctl(fd, CDROM_DRIVE_STATUS, slot);
+
+        inputs:
+          Slot number to be tested, always zero except for jukeboxes.
+          May also be special values CDSL_NONE or CDSL_CURRENT
+
+        outputs:
+          Ioctl return value will be one of the following values
+          from <linux/cdrom.h>:
+
+            CDS_NO_INFO         Information not available.
+            CDS_NO_DISC
+            CDS_TRAY_OPEN
+            CDS_DRIVE_NOT_READY
+            CDS_DISC_OK
+            -1                  error
+
+        error returns:
+          ENOSYS        Drive can't detect drive status
+          EINVAL        Slot number beyond capacity of drive
+          ENOMEM        Out of memory
+
+
+
+
+CDROM_DISC_STATUS               Get disc type, etc.
+
+        usage:
+
+          ioctl(fd, CDROM_DISC_STATUS, 0);
+
+        inputs:         none
+
+        outputs:
+          Ioctl return value will be one of the following values
+          from <linux/cdrom.h>:
+            CDS_NO_INFO
+            CDS_AUDIO
+            CDS_MIXED
+            CDS_XA_2_2
+            CDS_XA_2_1
+            CDS_DATA_1
+
+        error returns:  none at present
+
+        notes:
+          Source code comments state:
+
+            Ok, this is where problems start.  The current interface for
+            the CDROM_DISC_STATUS ioctl is flawed.  It makes the false
+            assumption that CDs are all CDS_DATA_1 or all CDS_AUDIO, etc.
+            Unfortunatly, while this is often the case, it is also
+            very common for CDs to have some tracks with data, and some
+            tracks with audio.  Just because I feel like it, I declare
+            the following to be the best way to cope.  If the CD has
+            ANY data tracks on it, it will be returned as a data CD.
+            If it has any XA tracks, I will return it as that.  Now I
+            could simplify this interface by combining these returns with
+            the above, but this more clearly demonstrates the problem
+            with the current interface.  Too bad this wasn't designed
+            to use bitmasks...         -Erik
+
+            Well, now we have the option CDS_MIXED: a mixed-type CD.
+            User level programmers might feel the ioctl is not very
+            useful.
+                        ---david
+
+
+
+
+CDROM_CHANGER_NSLOTS            Get number of slots
+
+        usage:
+
+          ioctl(fd, CDROM_CHANGER_NSLOTS, 0);
+
+        inputs:         none
+
+        outputs:
+          The ioctl return value will be the number of slots in a
+          CD changer.  Typically 1 for non-multi-disk devices.
+
+        error returns:  none
+
+
+
+CDROM_LOCKDOOR                  lock or unlock door
+
+        usage:
+
+          int lock;
+          ioctl(fd, CDROM_LOCKDOOR, lock);
+
+        inputs:
+          Door lock flag, 1=lock, 0=unlock
+
+        outputs:        none
+
+        error returns:
+          EDRIVE_CANT_DO_THIS   Door lock function not supported.
+          EBUSY                 Attempt to unlock when multiple users
+                                have the drive open and not CAP_SYS_ADMIN
+
+        notes:
+          As of 2.6.8.1, the lock flag is a global lock, meaning that
+          all CD drives will be locked or unlocked together.  This is
+          probably a bug.
+
+          The EDRIVE_CANT_DO_THIS value is defined in <linux/cdrom.h>
+          and is currently (2.6.8.1) the same as EOPNOTSUPP
+
+
+
+CDROM_DEBUG                     Turn debug messages on/off
+
+        usage:
+
+          int debug;
+          ioctl(fd, CDROM_DEBUG, debug);
+
+        inputs:
+          Cdrom debug flag, 0=disable, 1=enable
+
+        outputs:
+          The ioctl return value will be the new debug flag.
+
+        error return:
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+
+
+
+CDROM_GET_CAPABILITY            get capabilities
+
+        usage:
+
+          ioctl(fd, CDROM_GET_CAPABILITY, 0);
+
+        inputs:         none
+
+        outputs:
+          The ioctl return value is the current device capability
+          flags.  See CDC_CLOSE_TRAY, CDC_OPEN_TRAY, etc.
+
+
+
+CDROMAUDIOBUFSIZ                set the audio buffer size
+
+        usage:
+
+          int arg;
+          ioctl(fd, CDROMAUDIOBUFSIZ, val);
+
+        inputs:
+          New audio buffer size
+
+        outputs:
+          The ioctl return value is the new audio buffer size, or -1
+          on error.
+
+        error return:
+          ENOSYS        Not supported by this driver.
+
+        notes:
+          Not supported by all drivers.
+
+
+
+DVD_READ_STRUCT                 Read structure
+
+        usage:
+
+          dvd_struct s;
+          ioctl(fd, DVD_READ_STRUCT, &s);
+
+        inputs:
+          dvd_struct structure, containing:
+            type                specifies the information desired, one of
+                                DVD_STRUCT_PHYSICAL, DVD_STRUCT_COPYRIGHT,
+                                DVD_STRUCT_DISCKEY, DVD_STRUCT_BCA,
+                                DVD_STRUCT_MANUFACT
+            physical.layer_num  desired layer, indexed from 0
+            copyright.layer_num desired layer, indexed from 0
+            disckey.agid
+
+        outputs:
+          dvd_struct structure, containing:
+            physical            for type == DVD_STRUCT_PHYSICAL
+            copyright           for type == DVD_STRUCT_COPYRIGHT
+            disckey.value       for type == DVD_STRUCT_DISCKEY
+            bca.{len,value}     for type == DVD_STRUCT_BCA
+            manufact.{len,valu} for type == DVD_STRUCT_MANUFACT
+
+        error returns:
+          EINVAL        physical.layer_num exceeds number of layers
+          EIO           Recieved invalid response from drive
+
+
+
+DVD_WRITE_STRUCT                Write structure
+
+        Not implemented, as of 2.6.8.1
+
+
+
+DVD_AUTH                        Authentication
+
+        usage:
+
+          dvd_authinfo ai;
+          ioctl(fd, DVD_AUTH, &ai);
+
+        inputs:
+          dvd_authinfo structure.  See <linux/cdrom.h>
+
+        outputs:
+          dvd_authinfo structure.
+
+        error return:
+          ENOTTY        ai.type not recognized.
+
+
+
+CDROM_SEND_PACKET               send a packet to the drive
+
+        usage:
+
+          struct cdrom_generic_command cgc;
+          ioctl(fd, CDROM_SEND_PACKET, &cgc);
+
+        inputs:
+          cdrom_generic_command structure containing the packet to send.
+
+        outputs:        none
+          cdrom_generic_command structure containing results.
+
+        error return:
+          EIO           command failed.
+          EPERM         Operation not permitted, either because a
+                        write command was attempted on a drive which
+                        is opened read-only, or because the command
+                        requires CAP_SYS_RAWIO
+          EINVAL        cgc.data_direction not set
+
+
+
+CDROM_NEXT_WRITABLE             get next writable block
+
+        usage:
+
+          long next;
+          ioctl(fd, CDROM_NEXT_WRITABLE, &next);
+
+        inputs:         none
+
+        outputs:
+          The next writable block.
+
+        notes:
+          If the device does not support this ioctl directly, the
+          ioctl will return CDROM_LAST_WRITTEN + 7.
+
+
+
+CDROM_LAST_WRITTEN              get last block written on disc
+
+        usage:
+
+          long last;
+          ioctl(fd, CDROM_LAST_WRITTEN, &last);
+
+        inputs:         none
+
+        outputs:
+          The last block written on disc
+
+        notes:
+          If the device does not support this ioctl directly, the
+          result is derived from the disc's table of contents.  If the
+          table of contents can't be read, this ioctl returns an
+          error.
diff --git a/Documentation/ioctl/hdio.txt b/Documentation/ioctl/hdio.txt
new file mode 100644
index 000000000000..9a7aea0636a5
--- /dev/null
+++ b/Documentation/ioctl/hdio.txt
@@ -0,0 +1,1070 @@
+                Summary of HDIO_ ioctl calls.
+                ============================
+
+                Edward A. Falk <efalk@google.com>
+
+                November, 2004
+
+This document attempts to describe the ioctl(2) calls supported by
+the HD/IDE layer.  These are by-and-large implemented (as of Linux 2.6)
+in drivers/ide/ide.c and drivers/block/scsi_ioctl.c
+
+ioctl values are listed in <linux/hdreg.h>.  As of this writing, they
+are as follows:
+
+    ioctls that pass argument pointers to user space:
+
+        HDIO_GETGEO             get device geometry
+        HDIO_GET_UNMASKINTR     get current unmask setting
+        HDIO_GET_MULTCOUNT      get current IDE blockmode setting
+        HDIO_GET_QDMA           get use-qdma flag
+        HDIO_SET_XFER           set transfer rate via proc
+        HDIO_OBSOLETE_IDENTITY  OBSOLETE, DO NOT USE
+        HDIO_GET_KEEPSETTINGS   get keep-settings-on-reset flag
+        HDIO_GET_32BIT          get current io_32bit setting
+        HDIO_GET_NOWERR         get ignore-write-error flag
+        HDIO_GET_DMA            get use-dma flag
+        HDIO_GET_NICE           get nice flags
+        HDIO_GET_IDENTITY       get IDE identification info
+        HDIO_GET_WCACHE         get write cache mode on|off
+        HDIO_GET_ACOUSTIC       get acoustic value
+        HDIO_GET_ADDRESS        get sector addressing mode
+        HDIO_GET_BUSSTATE       get the bus state of the hwif
+        HDIO_TRISTATE_HWIF      execute a channel tristate
+        HDIO_DRIVE_RESET        execute a device reset
+        HDIO_DRIVE_TASKFILE     execute raw taskfile
+        HDIO_DRIVE_TASK         execute task and special drive command
+        HDIO_DRIVE_CMD          execute a special drive command
+        HDIO_DRIVE_CMD_AEB      HDIO_DRIVE_TASK
+
+    ioctls that pass non-pointer values:
+
+        HDIO_SET_MULTCOUNT      change IDE blockmode
+        HDIO_SET_UNMASKINTR     permit other irqs during I/O
+        HDIO_SET_KEEPSETTINGS   keep ioctl settings on reset
+        HDIO_SET_32BIT          change io_32bit flags
+        HDIO_SET_NOWERR         change ignore-write-error flag
+        HDIO_SET_DMA            change use-dma flag
+        HDIO_SET_PIO_MODE       reconfig interface to new speed
+        HDIO_SCAN_HWIF          register and (re)scan interface
+        HDIO_SET_NICE           set nice flags
+        HDIO_UNREGISTER_HWIF    unregister interface
+        HDIO_SET_WCACHE         change write cache enable-disable
+        HDIO_SET_ACOUSTIC       change acoustic behavior
+        HDIO_SET_BUSSTATE       set the bus state of the hwif
+        HDIO_SET_QDMA           change use-qdma flag
+        HDIO_SET_ADDRESS        change lba addressing modes
+
+        HDIO_SET_IDE_SCSI       Set scsi emulation mode on/off
+        HDIO_SET_SCSI_IDE       not implemented yet
+
+
+The information that follows was determined from reading kernel source
+code.  It is likely that some corrections will be made over time.
+
+
+
+
+
+
+
+General:
+
+        Unless otherwise specified, all ioctl calls return 0 on success
+        and -1 with errno set to an appropriate value on error.
+
+        Unless otherwise specified, all ioctl calls return -1 and set
+        errno to EFAULT on a failed attempt to copy data to or from user
+        address space.
+
+        Unless otherwise specified, all data structures and constants
+        are defined in <linux/hdreg.h>
+
+
+
+HDIO_GETGEO                     get device geometry
+
+        usage:
+
+          struct hd_geometry geom;
+          ioctl(fd, HDIO_GETGEO, &geom);
+
+
+        inputs:         none
+
+        outputs:
+
+          hd_geometry structure containing:
+
+            heads       number of heads
+            sectors     number of sectors/track
+            cylinders   number of cylinders, mod 65536
+            start       starting sector of this partition.
+
+
+        error returns:
+          EINVAL        if the device is not a disk drive or floppy drive,
+                        or if the user passes a null pointer
+
+
+        notes:
+
+          Not particularly useful with modern disk drives, whose geometry
+          is a polite fiction anyway.  Modern drives are addressed
+          purely by sector number nowadays (lba addressing), and the
+          drive geometry is an abstraction which is actually subject
+          to change.  Currently (as of Nov 2004), the geometry values
+          are the "bios" values -- presumably the values the drive had
+          when Linux first booted.
+
+          In addition, the cylinders field of the hd_geometry is an
+          unsigned short, meaning that on most architectures, this
+          ioctl will not return a meaningful value on drives with more
+          than 65535 tracks.
+
+          The start field is unsigned long, meaning that it will not
+          contain a meaningful value for disks over 219 Gb in size.
+
+
+
+
+HDIO_GET_UNMASKINTR             get current unmask setting
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_GET_UNMASKINTR, &val);
+
+        inputs:         none
+
+        outputs:
+          The value of the drive's current unmask setting
+
+
+
+HDIO_SET_UNMASKINTR             permit other irqs during I/O
+
+        usage:
+
+          unsigned long val;
+          ioctl(fd, HDIO_SET_UNMASKINTR, val);
+
+        inputs:
+          New value for unmask flag
+
+        outputs:        none
+
+        error return:
+          EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          EINVAL        value out of range [0 1]
+          EBUSY         Controller busy
+
+
+
+
+HDIO_GET_MULTCOUNT              get current IDE blockmode setting
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_GET_MULTCOUNT, &val);
+
+        inputs:         none
+
+        outputs:
+          The value of the current IDE block mode setting.  This
+          controls how many sectors the drive will transfer per
+          interrupt.
+
+
+
+HDIO_SET_MULTCOUNT              change IDE blockmode
+
+        usage:
+
+          int val;
+          ioctl(fd, HDIO_SET_MULTCOUNT, val);
+
+        inputs:
+          New value for IDE block mode setting.  This controls how many
+          sectors the drive will transfer per interrupt.
+
+        outputs:        none
+
+        error return:
+          EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          EINVAL        value out of range supported by disk.
+          EBUSY         Controller busy or blockmode already set.
+          EIO           Drive did not accept new block mode.
+
+        notes:
+
+          Source code comments read:
+
+            This is tightly woven into the driver->do_special can not
+            touch.  DON'T do it again until a total personality rewrite
+            is committed.
+
+          If blockmode has already been set, this ioctl will fail with
+          EBUSY
+
+
+
+HDIO_GET_QDMA                   get use-qdma flag
+
+        Not implemented, as of 2.6.8.1
+
+
+
+HDIO_SET_XFER                   set transfer rate via proc
+
+        Not implemented, as of 2.6.8.1
+
+
+
+HDIO_OBSOLETE_IDENTITY          OBSOLETE, DO NOT USE
+
+        Same as HDIO_GET_IDENTITY (see below), except that it only
+        returns the first 142 bytes of drive identity information.
+
+
+
+HDIO_GET_IDENTITY               get IDE identification info
+
+        usage:
+
+          unsigned char identity[512];
+          ioctl(fd, HDIO_GET_IDENTITY, identity);
+
+        inputs:         none
+
+        outputs:
+
+          ATA drive identity information.  For full description, see
+          the IDENTIFY DEVICE and IDENTIFY PACKET DEVICE commands in
+          the ATA specification.
+
+        error returns:
+          EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
+          ENOMSG        IDENTIFY DEVICE information not available
+
+        notes:
+
+          Returns information that was obtained when the drive was
+          probed.  Some of this information is subject to change, and
+          this ioctl does not re-probe the drive to update the
+          information.
+
+          This information is also available from /proc/ide/hdX/identify
+
+
+
+HDIO_GET_KEEPSETTINGS           get keep-settings-on-reset flag
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_GET_KEEPSETTINGS, &val);
+
+        inputs:         none
+
+        outputs:
+          The value of the current "keep settings" flag
+
+        notes:
+
+          When set, indicates that kernel should restore settings
+          after a drive reset.
+
+
+
+HDIO_SET_KEEPSETTINGS           keep ioctl settings on reset
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_SET_KEEPSETTINGS, val);
+
+        inputs:
+          New value for keep_settings flag
+
+        outputs:        none
+
+        error return:
+          EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          EINVAL        value out of range [0 1]
+          EBUSY         Controller busy
+
+
+
+HDIO_GET_32BIT                  get current io_32bit setting
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_GET_32BIT, &val);
+
+        inputs:         none
+
+        outputs:
+          The value of the current io_32bit setting
+
+        notes:
+
+          0=16-bit, 1=32-bit, 2,3 = 32bit+sync
+
+
+
+HDIO_GET_NOWERR                 get ignore-write-error flag
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_GET_NOWERR, &val);
+
+        inputs:         none
+
+        outputs:
+          The value of the current ignore-write-error flag
+
+
+
+HDIO_GET_DMA                    get use-dma flag
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_GET_DMA, &val);
+
+        inputs:         none
+
+        outputs:
+          The value of the current use-dma flag
+
+
+
+HDIO_GET_NICE                   get nice flags
+
+        usage:
+
+          long nice;
+          ioctl(fd, HDIO_GET_NICE, &nice);
+
+        inputs:         none
+
+        outputs:
+
+          The drive's "nice" values.
+
+        notes:
+
+          Per-drive flags which determine when the system will give more
+          bandwidth to other devices sharing the same IDE bus.
+          See <linux/hdreg.h>, near symbol IDE_NICE_DSC_OVERLAP.
+
+
+
+
+HDIO_SET_NICE                   set nice flags
+
+        usage:
+
+          unsigned long nice;
+          ...
+          ioctl(fd, HDIO_SET_NICE, nice);
+
+        inputs:
+          bitmask of nice flags.
+
+        outputs:        none
+
+        error returns:
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          EPERM         Flags other than DSC_OVERLAP and NICE_1 set.
+          EPERM         DSC_OVERLAP specified but not supported by drive
+
+        notes:
+
+          This ioctl sets the DSC_OVERLAP and NICE_1 flags from values
+          provided by the user.
+
+          Nice flags are listed in <linux/hdreg.h>, starting with
+          IDE_NICE_DSC_OVERLAP.  These values represent shifts.
+
+
+
+
+
+HDIO_GET_WCACHE                 get write cache mode on|off
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_GET_WCACHE, &val);
+
+        inputs:         none
+
+        outputs:
+          The value of the current write cache mode
+
+
+
+HDIO_GET_ACOUSTIC               get acoustic value
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_GET_ACOUSTIC, &val);
+
+        inputs:         none
+
+        outputs:
+          The value of the current acoustic settings
+
+        notes:
+
+          See HDIO_SET_ACOUSTIC
+
+
+
+HDIO_GET_ADDRESS
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_GET_ADDRESS, &val);
+
+        inputs:         none
+
+        outputs:
+          The value of the current addressing mode:
+            0 = 28-bit
+            1 = 48-bit
+            2 = 48-bit doing 28-bit
+            3 = 64-bit
+
+
+
+HDIO_GET_BUSSTATE               get the bus state of the hwif
+
+        usage:
+
+          long state;
+          ioctl(fd, HDIO_SCAN_HWIF, &state);
+
+        inputs:         none
+
+        outputs:
+          Current power state of the IDE bus.  One of BUSSTATE_OFF,
+          BUSSTATE_ON, or BUSSTATE_TRISTATE
+
+        error returns:
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+
+
+
+
+HDIO_SET_BUSSTATE               set the bus state of the hwif
+
+        usage:
+
+          int state;
+          ...
+          ioctl(fd, HDIO_SCAN_HWIF, state);
+
+        inputs:
+          Desired IDE power state.  One of BUSSTATE_OFF, BUSSTATE_ON,
+          or BUSSTATE_TRISTATE
+
+        outputs:        none
+
+        error returns:
+          EACCES        Access denied:  requires CAP_SYS_RAWIO
+          EOPNOTSUPP    Hardware interface does not support bus power control
+
+
+
+
+HDIO_TRISTATE_HWIF              execute a channel tristate
+
+        Not implemented, as of 2.6.8.1.  See HDIO_SET_BUSSTATE
+
+
+
+HDIO_DRIVE_RESET                execute a device reset
+
+        usage:
+
+          int args[3]
+          ...
+          ioctl(fd, HDIO_DRIVE_RESET, args);
+
+        inputs:         none
+
+        outputs:        none
+
+        error returns:
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+
+        notes:
+
+          Abort any current command, prevent anything else from being
+          queued, execute a reset on the device, and issue BLKRRPART
+          ioctl on the block device.
+
+          Executes an ATAPI soft reset if applicable, otherwise
+          executes an ATA soft reset on the controller.
+
+
+
+HDIO_DRIVE_TASKFILE             execute raw taskfile
+
+        Note:  If you don't have a copy of the ANSI ATA specification
+        handy, you should probably ignore this ioctl.
+
+        Execute an ATA disk command directly by writing the "taskfile"
+        registers of the drive.  Requires ADMIN and RAWIO access
+        privileges.
+
+        usage:
+
+          struct {
+            ide_task_request_t req_task;
+            u8 outbuf[OUTPUT_SIZE];
+            u8 inbuf[INPUT_SIZE];
+          } task;
+          memset(&task.req_task, 0, sizeof(task.req_task));
+          task.req_task.out_size = sizeof(task.outbuf);
+          task.req_task.in_size = sizeof(task.inbuf);
+          ...
+          ioctl(fd, HDIO_DRIVE_TASKFILE, &task);
+          ...
+
+        inputs:
+
+          (See below for details on memory area passed to ioctl.)
+
+          io_ports[8]   values to be written to taskfile registers
+          hob_ports[8]  high-order bytes, for extended commands.
+          out_flags     flags indicating which registers are valid
+          in_flags      flags indicating which registers should be returned
+          data_phase    see below
+          req_cmd       command type to be executed
+          out_size      size of output buffer
+          outbuf        buffer of data to be transmitted to disk
+          inbuf         buffer of data to be received from disk (see [1])
+
+        outputs:
+
+          io_ports[]    values returned in the taskfile registers
+          hob_ports[]   high-order bytes, for extended commands.
+          out_flags     flags indicating which registers are valid (see [2])
+          in_flags      flags indicating which registers should be returned
+          outbuf        buffer of data to be transmitted to disk (see [1])
+          inbuf         buffer of data to be received from disk
+
+        error returns:
+          EACCES        CAP_SYS_ADMIN or CAP_SYS_RAWIO privilege not set.
+          ENOMSG        Device is not a disk drive.
+          ENOMEM        Unable to allocate memory for task
+          EFAULT        req_cmd == TASKFILE_IN_OUT (not implemented as of 2.6.8)
+          EPERM         req_cmd == TASKFILE_MULTI_OUT and drive
+                        multi-count not yet set.
+          EIO           Drive failed the command.
+
+        notes:
+
+          [1] READ THE FOLLOWING NOTES *CAREFULLY*.  THIS IOCTL IS
+          FULL OF GOTCHAS.  Extreme caution should be used with using
+          this ioctl.  A mistake can easily corrupt data or hang the
+          system.
+
+          [2] Both the input and output buffers are copied from the
+          user and written back to the user, even when not used.
+
+          [3] If one or more bits are set in out_flags and in_flags is
+          zero, the following values are used for in_flags.all and
+          written back into in_flags on completion.
+
+           * IDE_TASKFILE_STD_IN_FLAGS | (IDE_HOB_STD_IN_FLAGS << 8)
+             if LBA48 addressing is enabled for the drive
+           * IDE_TASKFILE_STD_IN_FLAGS
+             if CHS/LBA28
+
+          The association between in_flags.all and each enable
+          bitfield flips depending on endianess; fortunately, TASKFILE
+          only uses inflags.b.data bit and ignores all other bits.
+          The end result is that, on any endian machines, it has no
+          effect other than modifying in_flags on completion.
+
+          [4] The default value of SELECT is (0xa0|DEV_bit|LBA_bit)
+          except for four drives per port chipsets.  For four drives
+          per port chipsets, it's (0xa0|DEV_bit|LBA_bit) for the first
+          pair and (0x80|DEV_bit|LBA_bit) for the second pair.
+
+          [5] The argument to the ioctl is a pointer to a region of
+          memory containing a ide_task_request_t structure, followed
+          by an optional buffer of data to be transmitted to the
+          drive, followed by an optional buffer to receive data from
+          the drive.
+
+          Command is passed to the disk drive via the ide_task_request_t
+          structure, which contains these fields:
+
+            io_ports[8]         values for the taskfile registers
+            hob_ports[8]        high-order bytes, for extended commands
+            out_flags           flags indicating which entries in the
+                                io_ports[] and hob_ports[] arrays
+                                contain valid values.  Type ide_reg_valid_t.
+            in_flags            flags indicating which entries in the
+                                io_ports[] and hob_ports[] arrays
+                                are expected to contain valid values
+                                on return.
+            data_phase          See below
+            req_cmd             Command type, see below
+            out_size            output (user->drive) buffer size, bytes
+            in_size             input (drive->user) buffer size, bytes
+
+          When out_flags is zero, the following registers are loaded.
+
+            HOB_FEATURE         If the drive supports LBA48
+            HOB_NSECTOR         If the drive supports LBA48
+            HOB_SECTOR          If the drive supports LBA48
+            HOB_LCYL            If the drive supports LBA48
+            HOB_HCYL            If the drive supports LBA48
+            FEATURE
+            NSECTOR
+            SECTOR
+            LCYL
+            HCYL
+            SELECT              First, masked with 0xE0 if LBA48, 0xEF
+                                otherwise; then, or'ed with the default
+                                value of SELECT.
+
+          If any bit in out_flags is set, the following registers are loaded.
+
+            HOB_DATA            If out_flags.b.data is set.  HOB_DATA will
+                                travel on DD8-DD15 on little endian machines
+                                and on DD0-DD7 on big endian machines.
+            DATA                If out_flags.b.data is set.  DATA will
+                                travel on DD0-DD7 on little endian machines
+                                and on DD8-DD15 on big endian machines.
+            HOB_NSECTOR         If out_flags.b.nsector_hob is set
+            HOB_SECTOR          If out_flags.b.sector_hob is set
+            HOB_LCYL            If out_flags.b.lcyl_hob is set
+            HOB_HCYL            If out_flags.b.hcyl_hob is set
+            FEATURE             If out_flags.b.feature is set
+            NSECTOR             If out_flags.b.nsector is set
+            SECTOR              If out_flags.b.sector is set
+            LCYL                If out_flags.b.lcyl is set
+            HCYL                If out_flags.b.hcyl is set
+            SELECT              Or'ed with the default value of SELECT and
+                                loaded regardless of out_flags.b.select.
+
+          Taskfile registers are read back from the drive into
+          {io|hob}_ports[] after the command completes iff one of the
+          following conditions is met; otherwise, the original values
+          will be written back, unchanged.
+
+            1. The drive fails the command (EIO).
+            2. One or more than one bits are set in out_flags.
+            3. The requested data_phase is TASKFILE_NO_DATA.
+
+            HOB_DATA            If in_flags.b.data is set.  It will contain
+                                DD8-DD15 on little endian machines and
+                                DD0-DD7 on big endian machines.
+            DATA                If in_flags.b.data is set.  It will contain
+                                DD0-DD7 on little endian machines and
+                                DD8-DD15 on big endian machines.
+            HOB_FEATURE         If the drive supports LBA48
+            HOB_NSECTOR         If the drive supports LBA48
+            HOB_SECTOR          If the drive supports LBA48
+            HOB_LCYL            If the drive supports LBA48
+            HOB_HCYL            If the drive supports LBA48
+            NSECTOR
+            SECTOR
+            LCYL
+            HCYL
+
+          The data_phase field describes the data transfer to be
+          performed.  Value is one of:
+
+            TASKFILE_IN
+            TASKFILE_MULTI_IN
+            TASKFILE_OUT
+            TASKFILE_MULTI_OUT
+            TASKFILE_IN_OUT
+            TASKFILE_IN_DMA
+            TASKFILE_IN_DMAQ            == IN_DMA (queueing not supported)
+            TASKFILE_OUT_DMA
+            TASKFILE_OUT_DMAQ           == OUT_DMA (queueing not supported)
+            TASKFILE_P_IN               unimplemented
+            TASKFILE_P_IN_DMA           unimplemented
+            TASKFILE_P_IN_DMAQ          unimplemented
+            TASKFILE_P_OUT              unimplemented
+            TASKFILE_P_OUT_DMA          unimplemented
+            TASKFILE_P_OUT_DMAQ         unimplemented
+
+          The req_cmd field classifies the command type.  It may be
+          one of:
+
+            IDE_DRIVE_TASK_NO_DATA
+            IDE_DRIVE_TASK_SET_XFER     unimplemented
+            IDE_DRIVE_TASK_IN
+            IDE_DRIVE_TASK_OUT          unimplemented
+            IDE_DRIVE_TASK_RAW_WRITE
+
+          [6] Do not access {in|out}_flags->all except for resetting
+          all the bits.  Always access individual bit fields.  ->all
+          value will flip depending on endianess.  For the same
+          reason, do not use IDE_{TASKFILE|HOB}_STD_{OUT|IN}_FLAGS
+          constants defined in hdreg.h.
+
+
+
+HDIO_DRIVE_CMD                  execute a special drive command
+
+        Note:  If you don't have a copy of the ANSI ATA specification
+        handy, you should probably ignore this ioctl.
+
+        usage:
+
+          u8 args[4+XFER_SIZE];
+          ...
+          ioctl(fd, HDIO_DRIVE_CMD, args);
+
+        inputs:
+
+          Commands other than WIN_SMART
+            args[0]     COMMAND
+            args[1]     NSECTOR
+            args[2]     FEATURE
+            args[3]     NSECTOR
+
+          WIN_SMART
+            args[0]     COMMAND
+            args[1]     SECTOR
+            args[2]     FEATURE
+            args[3]     NSECTOR
+
+        outputs:
+
+          args[] buffer is filled with register values followed by any
+          data returned by the disk.
+            args[0]     status
+            args[1]     error
+            args[2]     NSECTOR
+            args[3]     undefined
+            args[4+]    NSECTOR * 512 bytes of data returned by the command.
+
+        error returns:
+          EACCES        Access denied:  requires CAP_SYS_RAWIO
+          ENOMEM        Unable to allocate memory for task
+          EIO           Drive reports error
+
+        notes:
+
+          [1] For commands other than WIN_SMART, args[1] should equal
+          args[3].  SECTOR, LCYL and HCYL are undefined.  For
+          WIN_SMART, 0x4f and 0xc2 are loaded into LCYL and HCYL
+          respectively.  In both cases SELECT will contain the default
+          value for the drive.  Please refer to HDIO_DRIVE_TASKFILE
+          notes for the default value of SELECT.
+
+          [2] If NSECTOR value is greater than zero and the drive sets
+          DRQ when interrupting for the command, NSECTOR * 512 bytes
+          are read from the device into the area following NSECTOR.
+          In the above example, the area would be
+          args[4..4+XFER_SIZE].  16bit PIO is used regardless of
+          HDIO_SET_32BIT setting.
+
+          [3] If COMMAND == WIN_SETFEATURES && FEATURE == SETFEATURES_XFER
+          && NSECTOR >= XFER_SW_DMA_0 && the drive supports any DMA
+          mode, IDE driver will try to tune the transfer mode of the
+          drive accordingly.
+
+
+
+HDIO_DRIVE_TASK                 execute task and special drive command
+
+        Note:  If you don't have a copy of the ANSI ATA specification
+        handy, you should probably ignore this ioctl.
+
+        usage:
+
+          u8 args[7];
+          ...
+          ioctl(fd, HDIO_DRIVE_TASK, args);
+
+        inputs:
+
+          Taskfile register values:
+            args[0]     COMMAND
+            args[1]     FEATURE
+            args[2]     NSECTOR
+            args[3]     SECTOR
+            args[4]     LCYL
+            args[5]     HCYL
+            args[6]     SELECT
+
+        outputs:
+
+          Taskfile register values:
+            args[0]     status
+            args[1]     error
+            args[2]     NSECTOR
+            args[3]     SECTOR
+            args[4]     LCYL
+            args[5]     HCYL
+            args[6]     SELECT
+
+        error returns:
+          EACCES        Access denied:  requires CAP_SYS_RAWIO
+          ENOMEM        Unable to allocate memory for task
+          ENOMSG        Device is not a disk drive.
+          EIO           Drive failed the command.
+
+        notes:
+
+          [1] DEV bit (0x10) of SELECT register is ignored and the
+          appropriate value for the drive is used.  All other bits
+          are used unaltered.
+
+
+
+HDIO_DRIVE_CMD_AEB              HDIO_DRIVE_TASK
+
+        Not implemented, as of 2.6.8.1
+
+
+
+HDIO_SET_32BIT                  change io_32bit flags
+
+        usage:
+
+          int val;
+          ioctl(fd, HDIO_SET_32BIT, val);
+
+        inputs:
+          New value for io_32bit flag
+
+        outputs:        none
+
+        error return:
+          EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          EINVAL        value out of range [0 3]
+          EBUSY         Controller busy
+
+
+
+
+HDIO_SET_NOWERR                 change ignore-write-error flag
+
+        usage:
+
+          int val;
+          ioctl(fd, HDIO_SET_NOWERR, val);
+
+        inputs:
+          New value for ignore-write-error flag.  Used for ignoring
+          WRERR_STAT
+
+        outputs:        none
+
+        error return:
+          EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          EINVAL        value out of range [0 1]
+          EBUSY         Controller busy
+
+
+
+HDIO_SET_DMA                    change use-dma flag
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_SET_DMA, val);
+
+        inputs:
+          New value for use-dma flag
+
+        outputs:        none
+
+        error return:
+          EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          EINVAL        value out of range [0 1]
+          EBUSY         Controller busy
+
+
+
+HDIO_SET_PIO_MODE               reconfig interface to new speed
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_SET_PIO_MODE, val);
+
+        inputs:
+          New interface speed.
+
+        outputs:        none
+
+        error return:
+          EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          EINVAL        value out of range [0 255]
+          EBUSY         Controller busy
+
+
+
+HDIO_SCAN_HWIF                  register and (re)scan interface
+
+        usage:
+
+          int args[3]
+          ...
+          ioctl(fd, HDIO_SCAN_HWIF, args);
+
+        inputs:
+          args[0]       io address to probe
+          args[1]       control address to probe
+          args[2]       irq number
+
+        outputs:        none
+
+        error returns:
+          EACCES        Access denied:  requires CAP_SYS_RAWIO
+          EIO           Probe failed.
+
+        notes:
+
+          This ioctl initializes the addresses and irq for a disk
+          controller, probes for drives, and creates /proc/ide
+          interfaces as appropiate.
+
+
+
+HDIO_UNREGISTER_HWIF            unregister interface
+
+        usage:
+
+          int index;
+          ioctl(fd, HDIO_UNREGISTER_HWIF, index);
+
+        inputs:
+          index         index of hardware interface to unregister
+
+        outputs:        none
+
+        error returns:
+          EACCES        Access denied:  requires CAP_SYS_RAWIO
+
+        notes:
+
+          This ioctl removes a hardware interface from the kernel.
+
+          Currently (2.6.8) this ioctl silently fails if any drive on
+          the interface is busy.
+
+
+
+HDIO_SET_WCACHE                 change write cache enable-disable
+
+        usage:
+
+          int val;
+          ioctl(fd, HDIO_SET_WCACHE, val);
+
+        inputs:
+          New value for write cache enable
+
+        outputs:        none
+
+        error return:
+          EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          EINVAL        value out of range [0 1]
+          EBUSY         Controller busy
+
+
+
+HDIO_SET_ACOUSTIC               change acoustic behavior
+
+        usage:
+
+          int val;
+          ioctl(fd, HDIO_SET_ACOUSTIC, val);
+
+        inputs:
+          New value for drive acoustic settings
+
+        outputs:        none
+
+        error return:
+          EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          EINVAL        value out of range [0 254]
+          EBUSY         Controller busy
+
+
+
+HDIO_SET_QDMA                   change use-qdma flag
+
+        Not implemented, as of 2.6.8.1
+
+
+
+HDIO_SET_ADDRESS                change lba addressing modes
+
+        usage:
+
+          int val;
+          ioctl(fd, HDIO_SET_ADDRESS, val);
+
+        inputs:
+          New value for addressing mode
+            0 = 28-bit
+            1 = 48-bit
+            2 = 48-bit doing 28-bit
+
+        outputs:        none
+
+        error return:
+          EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          EINVAL        value out of range [0 2]
+          EBUSY         Controller busy
+          EIO           Drive does not support lba48 mode.
+
+
+HDIO_SET_IDE_SCSI
+
+        usage:
+
+          long val;
+          ioctl(fd, HDIO_SET_IDE_SCSI, val);
+
+        inputs:
+          New value for scsi emulation mode (?)
+
+        outputs:        none
+
+        error return:
+          EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
+          EACCES        Access denied:  requires CAP_SYS_ADMIN
+          EINVAL        value out of range [0 1]
+          EBUSY         Controller busy
+
+
+
+HDIO_SET_SCSI_IDE
+
+        Not implemented, as of 2.6.8.1
+
+