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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, CDROMCLOSETRAY, 0);
+
+
+	inputs:
+		none
+
+
+	outputs:
+		none
+
+
+	error returns:
+	  - ENOSYS	cd drive not capable of closing the tray
+	  - 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 or CDROM_LBA
+		  as per user request 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.
+		Unfortunately, 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		Received 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.