cdrom.rst

   1============================
   2Summary of CDROM ioctl calls
   3============================
   4
   5- Edward A. Falk <efalk@google.com>
   6
   7November, 2004
   8
   9This document attempts to describe the ioctl(2) calls supported by
  10the CDROM layer.  These are by-and-large implemented (as of Linux 2.6)
  11in drivers/cdrom/cdrom.c and drivers/block/scsi_ioctl.c
  12
  13ioctl values are listed in <linux/cdrom.h>.  As of this writing, they
  14are as follows:
  15
  16	========================  ===============================================
  17	CDROMPAUSE		  Pause Audio Operation
  18	CDROMRESUME		  Resume paused Audio Operation
  19	CDROMPLAYMSF		  Play Audio MSF (struct cdrom_msf)
  20	CDROMPLAYTRKIND		  Play Audio Track/index (struct cdrom_ti)
  21	CDROMREADTOCHDR		  Read TOC header (struct cdrom_tochdr)
  22	CDROMREADTOCENTRY	  Read TOC entry (struct cdrom_tocentry)
  23	CDROMSTOP		  Stop the cdrom drive
  24	CDROMSTART		  Start the cdrom drive
  25	CDROMEJECT		  Ejects the cdrom media
  26	CDROMVOLCTRL		  Control output volume (struct cdrom_volctrl)
  27	CDROMSUBCHNL		  Read subchannel data (struct cdrom_subchnl)
  28	CDROMREADMODE2		  Read CDROM mode 2 data (2336 Bytes)
  29				  (struct cdrom_read)
  30	CDROMREADMODE1		  Read CDROM mode 1 data (2048 Bytes)
  31				  (struct cdrom_read)
  32	CDROMREADAUDIO		  (struct cdrom_read_audio)
  33	CDROMEJECT_SW		  enable(1)/disable(0) auto-ejecting
  34	CDROMMULTISESSION	  Obtain the start-of-last-session
  35				  address of multi session disks
  36				  (struct cdrom_multisession)
  37	CDROM_GET_MCN		  Obtain the "Universal Product Code"
  38				  if available (struct cdrom_mcn)
  39	CDROM_GET_UPC		  Deprecated, use CDROM_GET_MCN instead.
  40	CDROMRESET		  hard-reset the drive
  41	CDROMVOLREAD		  Get the drive's volume setting
  42				  (struct cdrom_volctrl)
  43	CDROMREADRAW		  read data in raw mode (2352 Bytes)
  44				  (struct cdrom_read)
  45	CDROMREADCOOKED		  read data in cooked mode
  46	CDROMSEEK		  seek msf address
  47	CDROMPLAYBLK		  scsi-cd only, (struct cdrom_blk)
  48	CDROMREADALL		  read all 2646 bytes
  49	CDROMGETSPINDOWN	  return 4-bit spindown value
  50	CDROMSETSPINDOWN	  set 4-bit spindown value
  51	CDROMCLOSETRAY		  pendant of CDROMEJECT
  52	CDROM_SET_OPTIONS	  Set behavior options
  53	CDROM_CLEAR_OPTIONS	  Clear behavior options
  54	CDROM_SELECT_SPEED	  Set the CD-ROM speed
  55	CDROM_SELECT_DISC	  Select disc (for juke-boxes)
  56	CDROM_MEDIA_CHANGED	  Check is media changed
  57	CDROM_TIMED_MEDIA_CHANGE  Check if media changed
  58				  since given time
  59				  (struct cdrom_timed_media_change_info)
  60	CDROM_DRIVE_STATUS	  Get tray position, etc.
  61	CDROM_DISC_STATUS	  Get disc type, etc.
  62	CDROM_CHANGER_NSLOTS	  Get number of slots
  63	CDROM_LOCKDOOR		  lock or unlock door
  64	CDROM_DEBUG		  Turn debug messages on/off
  65	CDROM_GET_CAPABILITY	  get capabilities
  66	CDROMAUDIOBUFSIZ	  set the audio buffer size
  67	DVD_READ_STRUCT		  Read structure
  68	DVD_WRITE_STRUCT	  Write structure
  69	DVD_AUTH		  Authentication
  70	CDROM_SEND_PACKET	  send a packet to the drive
  71	CDROM_NEXT_WRITABLE	  get next writable block
  72	CDROM_LAST_WRITTEN	  get last block written on disc
  73	========================  ===============================================
  74
  75
  76The information that follows was determined from reading kernel source
  77code.  It is likely that some corrections will be made over time.
  78
  79------------------------------------------------------------------------------
  80
  81General:
  82
  83	Unless otherwise specified, all ioctl calls return 0 on success
  84	and -1 with errno set to an appropriate value on error.  (Some
  85	ioctls return non-negative data values.)
  86
  87	Unless otherwise specified, all ioctl calls return -1 and set
  88	errno to EFAULT on a failed attempt to copy data to or from user
  89	address space.
  90
  91	Individual drivers may return error codes not listed here.
  92
  93	Unless otherwise specified, all data structures and constants
  94	are defined in <linux/cdrom.h>
  95
  96------------------------------------------------------------------------------
  97
  98
  99CDROMPAUSE
 100	Pause Audio Operation
 101
 102
 103	usage::
 104
 105	  ioctl(fd, CDROMPAUSE, 0);
 106
 107
 108	inputs:
 109		none
 110
 111
 112	outputs:
 113		none
 114
 115
 116	error return:
 117	  - ENOSYS	cd drive not audio-capable.
 118
 119
 120CDROMRESUME
 121	Resume paused Audio Operation
 122
 123
 124	usage::
 125
 126	  ioctl(fd, CDROMRESUME, 0);
 127
 128
 129	inputs:
 130		none
 131
 132
 133	outputs:
 134		none
 135
 136
 137	error return:
 138	  - ENOSYS	cd drive not audio-capable.
 139
 140
 141CDROMPLAYMSF
 142	Play Audio MSF
 143
 144	(struct cdrom_msf)
 145
 146
 147	usage::
 148
 149	  struct cdrom_msf msf;
 150
 151	  ioctl(fd, CDROMPLAYMSF, &msf);
 152
 153	inputs:
 154		cdrom_msf structure, describing a segment of music to play
 155
 156
 157	outputs:
 158		none
 159
 160
 161	error return:
 162	  - ENOSYS	cd drive not audio-capable.
 163
 164	notes:
 165		- MSF stands for minutes-seconds-frames
 166		- LBA stands for logical block address
 167		- Segment is described as start and end times, where each time
 168		  is described as minutes:seconds:frames.
 169		  A frame is 1/75 of a second.
 170
 171
 172CDROMPLAYTRKIND
 173	Play Audio Track/index
 174
 175	(struct cdrom_ti)
 176
 177
 178	usage::
 179
 180	  struct cdrom_ti ti;
 181
 182	  ioctl(fd, CDROMPLAYTRKIND, &ti);
 183
 184	inputs:
 185		cdrom_ti structure, describing a segment of music to play
 186
 187
 188	outputs:
 189		none
 190
 191
 192	error return:
 193	  - ENOSYS	cd drive not audio-capable.
 194
 195	notes:
 196		- Segment is described as start and end times, where each time
 197		  is described as a track and an index.
 198
 199
 200
 201CDROMREADTOCHDR
 202	Read TOC header
 203
 204	(struct cdrom_tochdr)
 205
 206
 207	usage::
 208
 209	  cdrom_tochdr header;
 210
 211	  ioctl(fd, CDROMREADTOCHDR, &header);
 212
 213	inputs:
 214		cdrom_tochdr structure
 215
 216
 217	outputs:
 218		cdrom_tochdr structure
 219
 220
 221	error return:
 222	  - ENOSYS	cd drive not audio-capable.
 223
 224
 225
 226CDROMREADTOCENTRY
 227	Read TOC entry
 228
 229	(struct cdrom_tocentry)
 230
 231
 232	usage::
 233
 234	  struct cdrom_tocentry entry;
 235
 236	  ioctl(fd, CDROMREADTOCENTRY, &entry);
 237
 238	inputs:
 239		cdrom_tocentry structure
 240
 241
 242	outputs:
 243		cdrom_tocentry structure
 244
 245
 246	error return:
 247	  - ENOSYS	cd drive not audio-capable.
 248	  - EINVAL	entry.cdte_format not CDROM_MSF or CDROM_LBA
 249	  - EINVAL	requested track out of bounds
 250	  - EIO		I/O error reading TOC
 251
 252	notes:
 253		- TOC stands for Table Of Contents
 254		- MSF stands for minutes-seconds-frames
 255		- LBA stands for logical block address
 256
 257
 258
 259CDROMSTOP
 260	Stop the cdrom drive
 261
 262
 263	usage::
 264
 265	  ioctl(fd, CDROMSTOP, 0);
 266
 267
 268	inputs:
 269		none
 270
 271
 272	outputs:
 273		none
 274
 275
 276	error return:
 277	  - ENOSYS	cd drive not audio-capable.
 278
 279	notes:
 280	  - Exact interpretation of this ioctl depends on the device,
 281	    but most seem to spin the drive down.
 282
 283
 284CDROMSTART
 285	Start the cdrom drive
 286
 287
 288	usage::
 289
 290	  ioctl(fd, CDROMSTART, 0);
 291
 292
 293	inputs:
 294		none
 295
 296
 297	outputs:
 298		none
 299
 300
 301	error return:
 302	  - ENOSYS	cd drive not audio-capable.
 303
 304	notes:
 305	  - Exact interpretation of this ioctl depends on the device,
 306	    but most seem to spin the drive up and/or close the tray.
 307	    Other devices ignore the ioctl completely.
 308
 309
 310CDROMEJECT
 311	- Ejects the cdrom media
 312
 313
 314	usage::
 315
 316	  ioctl(fd, CDROMEJECT, 0);
 317
 318
 319	inputs:
 320		none
 321
 322
 323	outputs:
 324		none
 325
 326
 327	error returns:
 328	  - ENOSYS	cd drive not capable of ejecting
 329	  - EBUSY	other processes are accessing drive, or door is locked
 330
 331	notes:
 332		- See CDROM_LOCKDOOR, below.
 333
 334
 335
 336
 337CDROMCLOSETRAY
 338	pendant of CDROMEJECT
 339
 340
 341	usage::
 342
 343	  ioctl(fd, CDROMCLOSETRAY, 0);
 344
 345
 346	inputs:
 347		none
 348
 349
 350	outputs:
 351		none
 352
 353
 354	error returns:
 355	  - ENOSYS	cd drive not capable of closing the tray
 356	  - EBUSY	other processes are accessing drive, or door is locked
 357
 358	notes:
 359		- See CDROM_LOCKDOOR, below.
 360
 361
 362
 363
 364CDROMVOLCTRL
 365	Control output volume (struct cdrom_volctrl)
 366
 367
 368	usage::
 369
 370	  struct cdrom_volctrl volume;
 371
 372	  ioctl(fd, CDROMVOLCTRL, &volume);
 373
 374	inputs:
 375		cdrom_volctrl structure containing volumes for up to 4
 376		channels.
 377
 378	outputs:
 379		none
 380
 381
 382	error return:
 383	  - ENOSYS	cd drive not audio-capable.
 384
 385
 386
 387CDROMVOLREAD
 388	Get the drive's volume setting
 389
 390	(struct cdrom_volctrl)
 391
 392
 393	usage::
 394
 395	  struct cdrom_volctrl volume;
 396
 397	  ioctl(fd, CDROMVOLREAD, &volume);
 398
 399	inputs:
 400		none
 401
 402
 403	outputs:
 404		The current volume settings.
 405
 406
 407	error return:
 408	  - ENOSYS	cd drive not audio-capable.
 409
 410
 411
 412CDROMSUBCHNL
 413	Read subchannel data
 414
 415	(struct cdrom_subchnl)
 416
 417
 418	usage::
 419
 420	  struct cdrom_subchnl q;
 421
 422	  ioctl(fd, CDROMSUBCHNL, &q);
 423
 424	inputs:
 425		cdrom_subchnl structure
 426
 427
 428	outputs:
 429		cdrom_subchnl structure
 430
 431
 432	error return:
 433	  - ENOSYS	cd drive not audio-capable.
 434	  - EINVAL	format not CDROM_MSF or CDROM_LBA
 435
 436	notes:
 437		- Format is converted to CDROM_MSF or CDROM_LBA
 438		  as per user request on return
 439
 440
 441
 442CDROMREADRAW
 443	read data in raw mode (2352 Bytes)
 444
 445	(struct cdrom_read)
 446
 447	usage::
 448
 449	  union {
 450
 451	    struct cdrom_msf msf;		/* input */
 452	    char buffer[CD_FRAMESIZE_RAW];	/* return */
 453	  } arg;
 454	  ioctl(fd, CDROMREADRAW, &arg);
 455
 456	inputs:
 457		cdrom_msf structure indicating an address to read.
 458
 459		Only the start values are significant.
 460
 461	outputs:
 462		Data written to address provided by user.
 463
 464
 465	error return:
 466	  - EINVAL	address less than 0, or msf less than 0:2:0
 467	  - ENOMEM	out of memory
 468
 469	notes:
 470		- As of 2.6.8.1, comments in <linux/cdrom.h> indicate that this
 471		  ioctl accepts a cdrom_read structure, but actual source code
 472		  reads a cdrom_msf structure and writes a buffer of data to
 473		  the same address.
 474
 475		- MSF values are converted to LBA values via this formula::
 476
 477		    lba = (((m * CD_SECS) + s) * CD_FRAMES + f) - CD_MSF_OFFSET;
 478
 479
 480
 481
 482CDROMREADMODE1
 483	Read CDROM mode 1 data (2048 Bytes)
 484
 485	(struct cdrom_read)
 486
 487	notes:
 488		Identical to CDROMREADRAW except that block size is
 489		CD_FRAMESIZE (2048) bytes
 490
 491
 492
 493CDROMREADMODE2
 494	Read CDROM mode 2 data (2336 Bytes)
 495
 496	(struct cdrom_read)
 497
 498	notes:
 499		Identical to CDROMREADRAW except that block size is
 500		CD_FRAMESIZE_RAW0 (2336) bytes
 501
 502
 503
 504CDROMREADAUDIO
 505	(struct cdrom_read_audio)
 506
 507	usage::
 508
 509	  struct cdrom_read_audio ra;
 510
 511	  ioctl(fd, CDROMREADAUDIO, &ra);
 512
 513	inputs:
 514		cdrom_read_audio structure containing read start
 515		point and length
 516
 517	outputs:
 518		audio data, returned to buffer indicated by ra
 519
 520
 521	error return:
 522	  - EINVAL	format not CDROM_MSF or CDROM_LBA
 523	  - EINVAL	nframes not in range [1 75]
 524	  - ENXIO	drive has no queue (probably means invalid fd)
 525	  - ENOMEM	out of memory
 526
 527
 528CDROMEJECT_SW
 529	enable(1)/disable(0) auto-ejecting
 530
 531
 532	usage::
 533
 534	  int val;
 535
 536	  ioctl(fd, CDROMEJECT_SW, val);
 537
 538	inputs:
 539		Flag specifying auto-eject flag.
 540
 541
 542	outputs:
 543		none
 544
 545
 546	error return:
 547	  - ENOSYS	Drive is not capable of ejecting.
 548	  - EBUSY	Door is locked
 549
 550
 551
 552
 553CDROMMULTISESSION
 554	Obtain the start-of-last-session address of multi session disks
 555
 556	(struct cdrom_multisession)
 557
 558	usage::
 559
 560	  struct cdrom_multisession ms_info;
 561
 562	  ioctl(fd, CDROMMULTISESSION, &ms_info);
 563
 564	inputs:
 565		cdrom_multisession structure containing desired
 566
 567	  format.
 568
 569	outputs:
 570		cdrom_multisession structure is filled with last_session
 571		information.
 572
 573	error return:
 574	  - EINVAL	format not CDROM_MSF or CDROM_LBA
 575
 576
 577CDROM_GET_MCN
 578	Obtain the "Universal Product Code"
 579	if available
 580
 581	(struct cdrom_mcn)
 582
 583
 584	usage::
 585
 586	  struct cdrom_mcn mcn;
 587
 588	  ioctl(fd, CDROM_GET_MCN, &mcn);
 589
 590	inputs:
 591		none
 592
 593
 594	outputs:
 595		Universal Product Code
 596
 597
 598	error return:
 599	  - ENOSYS	Drive is not capable of reading MCN data.
 600
 601	notes:
 602		- Source code comments state::
 603
 604		    The following function is implemented, although very few
 605		    audio discs give Universal Product Code information, which
 606		    should just be the Medium Catalog Number on the box.  Note,
 607		    that the way the code is written on the CD is /not/ uniform
 608		    across all discs!
 609
 610
 611
 612
 613CDROM_GET_UPC
 614	CDROM_GET_MCN  (deprecated)
 615
 616
 617	Not implemented, as of 2.6.8.1
 618
 619
 620
 621CDROMRESET
 622	hard-reset the drive
 623
 624
 625	usage::
 626
 627	  ioctl(fd, CDROMRESET, 0);
 628
 629
 630	inputs:
 631		none
 632
 633
 634	outputs:
 635		none
 636
 637
 638	error return:
 639	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
 640	  - ENOSYS	Drive is not capable of resetting.
 641
 642
 643
 644
 645CDROMREADCOOKED
 646	read data in cooked mode
 647
 648
 649	usage::
 650
 651	  u8 buffer[CD_FRAMESIZE]
 652
 653	  ioctl(fd, CDROMREADCOOKED, buffer);
 654
 655	inputs:
 656		none
 657
 658
 659	outputs:
 660		2048 bytes of data, "cooked" mode.
 661
 662
 663	notes:
 664		Not implemented on all drives.
 665
 666
 667
 668
 669
 670CDROMREADALL
 671	read all 2646 bytes
 672
 673
 674	Same as CDROMREADCOOKED, but reads 2646 bytes.
 675
 676
 677
 678CDROMSEEK
 679	seek msf address
 680
 681
 682	usage::
 683
 684	  struct cdrom_msf msf;
 685
 686	  ioctl(fd, CDROMSEEK, &msf);
 687
 688	inputs:
 689		MSF address to seek to.
 690
 691
 692	outputs:
 693		none
 694
 695
 696
 697
 698CDROMPLAYBLK
 699	scsi-cd only
 700
 701	(struct cdrom_blk)
 702
 703
 704	usage::
 705
 706	  struct cdrom_blk blk;
 707
 708	  ioctl(fd, CDROMPLAYBLK, &blk);
 709
 710	inputs:
 711		Region to play
 712
 713
 714	outputs:
 715		none
 716
 717
 718
 719
 720CDROMGETSPINDOWN
 721	Obsolete, was ide-cd only
 722
 723
 724	usage::
 725
 726	  char spindown;
 727
 728	  ioctl(fd, CDROMGETSPINDOWN, &spindown);
 729
 730	inputs:
 731		none
 732
 733
 734	outputs:
 735		The value of the current 4-bit spindown value.
 736
 737
 738
 739
 740
 741CDROMSETSPINDOWN
 742	Obsolete, was ide-cd only
 743
 744
 745	usage::
 746
 747	  char spindown
 748
 749	  ioctl(fd, CDROMSETSPINDOWN, &spindown);
 750
 751	inputs:
 752		4-bit value used to control spindown (TODO: more detail here)
 753
 754
 755	outputs:
 756		none
 757
 758
 759
 760
 761
 762
 763CDROM_SET_OPTIONS
 764	Set behavior options
 765
 766
 767	usage::
 768
 769	  int options;
 770
 771	  ioctl(fd, CDROM_SET_OPTIONS, options);
 772
 773	inputs:
 774		New values for drive options.  The logical 'or' of:
 775
 776	    ==============      ==================================
 777	    CDO_AUTO_CLOSE	close tray on first open(2)
 778	    CDO_AUTO_EJECT	open tray on last release
 779	    CDO_USE_FFLAGS	use O_NONBLOCK information on open
 780	    CDO_LOCK		lock tray on open files
 781	    CDO_CHECK_TYPE	check type on open for data
 782	    ==============      ==================================
 783
 784	outputs:
 785		Returns the resulting options settings in the
 786		ioctl return value.  Returns -1 on error.
 787
 788	error return:
 789	  - ENOSYS	selected option(s) not supported by drive.
 790
 791
 792
 793
 794CDROM_CLEAR_OPTIONS
 795	Clear behavior options
 796
 797
 798	Same as CDROM_SET_OPTIONS, except that selected options are
 799	turned off.
 800
 801
 802
 803CDROM_SELECT_SPEED
 804	Set the CD-ROM speed
 805
 806
 807	usage::
 808
 809	  int speed;
 810
 811	  ioctl(fd, CDROM_SELECT_SPEED, speed);
 812
 813	inputs:
 814		New drive speed.
 815
 816
 817	outputs:
 818		none
 819
 820
 821	error return:
 822	  - ENOSYS	speed selection not supported by drive.
 823
 824
 825
 826CDROM_SELECT_DISC
 827	Select disc (for juke-boxes)
 828
 829
 830	usage::
 831
 832	  int disk;
 833
 834	  ioctl(fd, CDROM_SELECT_DISC, disk);
 835
 836	inputs:
 837		Disk to load into drive.
 838
 839
 840	outputs:
 841		none
 842
 843
 844	error return:
 845	  - EINVAL	Disk number beyond capacity of drive
 846
 847
 848
 849CDROM_MEDIA_CHANGED
 850	Check is media changed
 851
 852
 853	usage::
 854
 855	  int slot;
 856
 857	  ioctl(fd, CDROM_MEDIA_CHANGED, slot);
 858
 859	inputs:
 860		Slot number to be tested, always zero except for jukeboxes.
 861
 862		May also be special values CDSL_NONE or CDSL_CURRENT
 863
 864	outputs:
 865		Ioctl return value is 0 or 1 depending on whether the media
 866
 867	  has been changed, or -1 on error.
 868
 869	error returns:
 870	  - ENOSYS	Drive can't detect media change
 871	  - EINVAL	Slot number beyond capacity of drive
 872	  - ENOMEM	Out of memory
 873
 874
 875
 876CDROM_DRIVE_STATUS
 877	Get tray position, etc.
 878
 879
 880	usage::
 881
 882	  int slot;
 883
 884	  ioctl(fd, CDROM_DRIVE_STATUS, slot);
 885
 886	inputs:
 887		Slot number to be tested, always zero except for jukeboxes.
 888
 889		May also be special values CDSL_NONE or CDSL_CURRENT
 890
 891	outputs:
 892		Ioctl return value will be one of the following values
 893
 894	  from <linux/cdrom.h>:
 895
 896	    =================== ==========================
 897	    CDS_NO_INFO		Information not available.
 898	    CDS_NO_DISC
 899	    CDS_TRAY_OPEN
 900	    CDS_DRIVE_NOT_READY
 901	    CDS_DISC_OK
 902	    -1			error
 903	    =================== ==========================
 904
 905	error returns:
 906	  - ENOSYS	Drive can't detect drive status
 907	  - EINVAL	Slot number beyond capacity of drive
 908	  - ENOMEM	Out of memory
 909
 910
 911
 912
 913CDROM_DISC_STATUS
 914	Get disc type, etc.
 915
 916
 917	usage::
 918
 919	  ioctl(fd, CDROM_DISC_STATUS, 0);
 920
 921
 922	inputs:
 923		none
 924
 925
 926	outputs:
 927		Ioctl return value will be one of the following values
 928
 929	  from <linux/cdrom.h>:
 930
 931	    - CDS_NO_INFO
 932	    - CDS_AUDIO
 933	    - CDS_MIXED
 934	    - CDS_XA_2_2
 935	    - CDS_XA_2_1
 936	    - CDS_DATA_1
 937
 938	error returns:
 939		none at present
 940
 941	notes:
 942	    - Source code comments state::
 943
 944
 945		Ok, this is where problems start.  The current interface for
 946		the CDROM_DISC_STATUS ioctl is flawed.  It makes the false
 947		assumption that CDs are all CDS_DATA_1 or all CDS_AUDIO, etc.
 948		Unfortunately, while this is often the case, it is also
 949		very common for CDs to have some tracks with data, and some
 950		tracks with audio.	Just because I feel like it, I declare
 951		the following to be the best way to cope.  If the CD has
 952		ANY data tracks on it, it will be returned as a data CD.
 953		If it has any XA tracks, I will return it as that.	Now I
 954		could simplify this interface by combining these returns with
 955		the above, but this more clearly demonstrates the problem
 956		with the current interface.  Too bad this wasn't designed
 957		to use bitmasks...	       -Erik
 958
 959		Well, now we have the option CDS_MIXED: a mixed-type CD.
 960		User level programmers might feel the ioctl is not very
 961		useful.
 962				---david
 963
 964
 965
 966
 967CDROM_CHANGER_NSLOTS
 968	Get number of slots
 969
 970
 971	usage::
 972
 973	  ioctl(fd, CDROM_CHANGER_NSLOTS, 0);
 974
 975
 976	inputs:
 977		none
 978
 979
 980	outputs:
 981		The ioctl return value will be the number of slots in a
 982		CD changer.  Typically 1 for non-multi-disk devices.
 983
 984	error returns:
 985		none
 986
 987
 988
 989CDROM_LOCKDOOR
 990	lock or unlock door
 991
 992
 993	usage::
 994
 995	  int lock;
 996
 997	  ioctl(fd, CDROM_LOCKDOOR, lock);
 998
 999	inputs:
1000		Door lock flag, 1=lock, 0=unlock
1001
1002
1003	outputs:
1004		none
1005
1006
1007	error returns:
1008	  - EDRIVE_CANT_DO_THIS
1009
1010				Door lock function not supported.
1011	  - EBUSY
1012
1013				Attempt to unlock when multiple users
1014				have the drive open and not CAP_SYS_ADMIN
1015
1016	notes:
1017		As of 2.6.8.1, the lock flag is a global lock, meaning that
1018		all CD drives will be locked or unlocked together.  This is
1019		probably a bug.
1020
1021		The EDRIVE_CANT_DO_THIS value is defined in <linux/cdrom.h>
1022		and is currently (2.6.8.1) the same as EOPNOTSUPP
1023
1024
1025
1026CDROM_DEBUG
1027	Turn debug messages on/off
1028
1029
1030	usage::
1031
1032	  int debug;
1033
1034	  ioctl(fd, CDROM_DEBUG, debug);
1035
1036	inputs:
1037		Cdrom debug flag, 0=disable, 1=enable
1038
1039
1040	outputs:
1041		The ioctl return value will be the new debug flag.
1042
1043
1044	error return:
1045	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
1046
1047
1048
1049CDROM_GET_CAPABILITY
1050	get capabilities
1051
1052
1053	usage::
1054
1055	  ioctl(fd, CDROM_GET_CAPABILITY, 0);
1056
1057
1058	inputs:
1059		none
1060
1061
1062	outputs:
1063		The ioctl return value is the current device capability
1064		flags.  See CDC_CLOSE_TRAY, CDC_OPEN_TRAY, etc.
1065
1066
1067
1068CDROMAUDIOBUFSIZ
1069	set the audio buffer size
1070
1071
1072	usage::
1073
1074	  int arg;
1075
1076	  ioctl(fd, CDROMAUDIOBUFSIZ, val);
1077
1078	inputs:
1079		New audio buffer size
1080
1081
1082	outputs:
1083		The ioctl return value is the new audio buffer size, or -1
1084		on error.
1085
1086	error return:
1087	  - ENOSYS	Not supported by this driver.
1088
1089	notes:
1090		Not supported by all drivers.
1091
1092
1093
1094
1095DVD_READ_STRUCT			Read structure
1096
1097	usage::
1098
1099	  dvd_struct s;
1100
1101	  ioctl(fd, DVD_READ_STRUCT, &s);
1102
1103	inputs:
1104		dvd_struct structure, containing:
1105
1106	    =================== ==========================================
1107	    type		specifies the information desired, one of
1108				DVD_STRUCT_PHYSICAL, DVD_STRUCT_COPYRIGHT,
1109				DVD_STRUCT_DISCKEY, DVD_STRUCT_BCA,
1110				DVD_STRUCT_MANUFACT
1111	    physical.layer_num	desired layer, indexed from 0
1112	    copyright.layer_num	desired layer, indexed from 0
1113	    disckey.agid
1114	    =================== ==========================================
1115
1116	outputs:
1117		dvd_struct structure, containing:
1118
1119	    =================== ================================
1120	    physical		for type == DVD_STRUCT_PHYSICAL
1121	    copyright		for type == DVD_STRUCT_COPYRIGHT
1122	    disckey.value	for type == DVD_STRUCT_DISCKEY
1123	    bca.{len,value}	for type == DVD_STRUCT_BCA
1124	    manufact.{len,valu}	for type == DVD_STRUCT_MANUFACT
1125	    =================== ================================
1126
1127	error returns:
1128	  - EINVAL	physical.layer_num exceeds number of layers
1129	  - EIO		Received invalid response from drive
1130
1131
1132
1133DVD_WRITE_STRUCT		Write structure
1134
1135	Not implemented, as of 2.6.8.1
1136
1137
1138
1139DVD_AUTH			Authentication
1140
1141	usage::
1142
1143	  dvd_authinfo ai;
1144
1145	  ioctl(fd, DVD_AUTH, &ai);
1146
1147	inputs:
1148		dvd_authinfo structure.  See <linux/cdrom.h>
1149
1150
1151	outputs:
1152		dvd_authinfo structure.
1153
1154
1155	error return:
1156	  - ENOTTY	ai.type not recognized.
1157
1158
1159
1160CDROM_SEND_PACKET
1161	send a packet to the drive
1162
1163
1164	usage::
1165
1166	  struct cdrom_generic_command cgc;
1167
1168	  ioctl(fd, CDROM_SEND_PACKET, &cgc);
1169
1170	inputs:
1171		cdrom_generic_command structure containing the packet to send.
1172
1173
1174	outputs:
1175		none
1176
1177	  cdrom_generic_command structure containing results.
1178
1179	error return:
1180	  - EIO
1181
1182			command failed.
1183	  - EPERM
1184
1185			Operation not permitted, either because a
1186			write command was attempted on a drive which
1187			is opened read-only, or because the command
1188			requires CAP_SYS_RAWIO
1189	  - EINVAL
1190
1191			cgc.data_direction not set
1192
1193
1194
1195CDROM_NEXT_WRITABLE
1196	get next writable block
1197
1198
1199	usage::
1200
1201	  long next;
1202
1203	  ioctl(fd, CDROM_NEXT_WRITABLE, &next);
1204
1205	inputs:
1206		none
1207
1208
1209	outputs:
1210		The next writable block.
1211
1212
1213	notes:
1214		If the device does not support this ioctl directly, the
1215
1216	  ioctl will return CDROM_LAST_WRITTEN + 7.
1217
1218
1219
1220CDROM_LAST_WRITTEN
1221	get last block written on disc
1222
1223
1224	usage::
1225
1226	  long last;
1227
1228	  ioctl(fd, CDROM_LAST_WRITTEN, &last);
1229
1230	inputs:
1231		none
1232
1233
1234	outputs:
1235		The last block written on disc
1236
1237
1238	notes:
1239		If the device does not support this ioctl directly, the
1240		result is derived from the disc's table of contents.  If the
1241		table of contents can't be read, this ioctl returns an
1242		error.