summaryrefslogtreecommitdiffstats
path: root/kernel/Documentation/ioctl/cdrom.txt
blob: 59df81c8da2b86dd71394ccb85ab34bc1cba4595 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
		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 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.