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Linus Torvalds1da177e2005-04-16 15:20:36 -07001IDE-CD driver documentation
2Originally by scott snyder <snyder@fnald0.fnal.gov> (19 May 1996)
3Carrying on the torch is: Erik Andersen <andersee@debian.org>
4New maintainers (19 Oct 1998): Jens Axboe <axboe@image.dk>
5
61. Introduction
7---------------
8
9The ide-cd driver should work with all ATAPI ver 1.2 to ATAPI 2.6 compliant
10CDROM drives which attach to an IDE interface. Note that some CDROM vendors
11(including Mitsumi, Sony, Creative, Aztech, and Goldstar) have made
12both ATAPI-compliant drives and drives which use a proprietary
13interface. If your drive uses one of those proprietary interfaces,
14this driver will not work with it (but one of the other CDROM drivers
15probably will). This driver will not work with `ATAPI' drives which
16attach to the parallel port. In addition, there is at least one drive
17(CyCDROM CR520ie) which attaches to the IDE port but is not ATAPI;
18this driver will not work with drives like that either (but see the
19aztcd driver).
20
21This driver provides the following features:
22
23 - Reading from data tracks, and mounting ISO 9660 filesystems.
24
25 - Playing audio tracks. Most of the CDROM player programs floating
26 around should work; I usually use Workman.
27
28 - Multisession support.
29
30 - On drives which support it, reading digital audio data directly
31 from audio tracks. The program cdda2wav can be used for this.
32 Note, however, that only some drives actually support this.
33
34 - There is now support for CDROM changers which comply with the
35 ATAPI 2.6 draft standard (such as the NEC CDR-251). This additional
36 functionality includes a function call to query which slot is the
37 currently selected slot, a function call to query which slots contain
38 CDs, etc. A sample program which demonstrates this functionality is
39 appended to the end of this file. The Sanyo 3-disc changer
40 (which does not conform to the standard) is also now supported.
41 Please note the driver refers to the first CD as slot # 0.
42
43
442. Installation
45---------------
46
470. The ide-cd relies on the ide disk driver. See
48 Documentation/ide.txt for up-to-date information on the ide
49 driver.
50
511. Make sure that the ide and ide-cd drivers are compiled into the
52 kernel you're using. When configuring the kernel, in the section
53 entitled "Floppy, IDE, and other block devices", say either `Y'
54 (which will compile the support directly into the kernel) or `M'
55 (to compile support as a module which can be loaded and unloaded)
56 to the options:
57
58 Enhanced IDE/MFM/RLL disk/cdrom/tape/floppy support
59 Include IDE/ATAPI CDROM support
60
61 and `no' to
62
63 Use old disk-only driver on primary interface
64
65 Depending on what type of IDE interface you have, you may need to
66 specify additional configuration options. See
67 Documentation/ide.txt.
68
692. You should also ensure that the iso9660 filesystem is either
70 compiled into the kernel or available as a loadable module. You
71 can see if a filesystem is known to the kernel by catting
72 /proc/filesystems.
73
743. The CDROM drive should be connected to the host on an IDE
75 interface. Each interface on a system is defined by an I/O port
76 address and an IRQ number, the standard assignments being
77 0x1f0 and 14 for the primary interface and 0x170 and 15 for the
78 secondary interface. Each interface can control up to two devices,
79 where each device can be a hard drive, a CDROM drive, a floppy drive,
80 or a tape drive. The two devices on an interface are called `master'
81 and `slave'; this is usually selectable via a jumper on the drive.
82
83 Linux names these devices as follows. The master and slave devices
84 on the primary IDE interface are called `hda' and `hdb',
85 respectively. The drives on the secondary interface are called
86 `hdc' and `hdd'. (Interfaces at other locations get other letters
87 in the third position; see Documentation/ide.txt.)
88
89 If you want your CDROM drive to be found automatically by the
90 driver, you should make sure your IDE interface uses either the
91 primary or secondary addresses mentioned above. In addition, if
92 the CDROM drive is the only device on the IDE interface, it should
93 be jumpered as `master'. (If for some reason you cannot configure
94 your system in this manner, you can probably still use the driver.
95 You may have to pass extra configuration information to the kernel
96 when you boot, however. See Documentation/ide.txt for more
97 information.)
98
994. Boot the system. If the drive is recognized, you should see a
100 message which looks like
101
102 hdb: NEC CD-ROM DRIVE:260, ATAPI CDROM drive
103
104 If you do not see this, see section 5 below.
105
1065. You may want to create a symbolic link /dev/cdrom pointing to the
107 actual device. You can do this with the command
108
109 ln -s /dev/hdX /dev/cdrom
110
111 where X should be replaced by the letter indicating where your
112 drive is installed.
113
1146. You should be able to see any error messages from the driver with
115 the `dmesg' command.
116
117
1183. Basic usage
119--------------
120
121An ISO 9660 CDROM can be mounted by putting the disc in the drive and
122typing (as root)
123
124 mount -t iso9660 /dev/cdrom /mnt/cdrom
125
126where it is assumed that /dev/cdrom is a link pointing to the actual
127device (as described in step 5 of the last section) and /mnt/cdrom is
128an empty directory. You should now be able to see the contents of the
129CDROM under the /mnt/cdrom directory. If you want to eject the CDROM,
130you must first dismount it with a command like
131
132 umount /mnt/cdrom
133
134Note that audio CDs cannot be mounted.
135
136Some distributions set up /etc/fstab to always try to mount a CDROM
137filesystem on bootup. It is not required to mount the CDROM in this
138manner, though, and it may be a nuisance if you change CDROMs often.
139You should feel free to remove the cdrom line from /etc/fstab and
140mount CDROMs manually if that suits you better.
141
142Multisession and photocd discs should work with no special handling.
143The hpcdtoppm package (ftp.gwdg.de:/pub/linux/hpcdtoppm/) may be
144useful for reading photocds.
145
146To play an audio CD, you should first unmount and remove any data
147CDROM. Any of the CDROM player programs should then work (workman,
148workbone, cdplayer, etc.). Lacking anything else, you could use the
149cdtester program in Documentation/cdrom/sbpcd.
150
151On a few drives, you can read digital audio directly using a program
152such as cdda2wav. The only types of drive which I've heard support
153this are Sony and Toshiba drives. You will get errors if you try to
154use this function on a drive which does not support it.
155
156For supported changers, you can use the `cdchange' program (appended to
157the end of this file) to switch between changer slots. Note that the
158drive should be unmounted before attempting this. The program takes
159two arguments: the CDROM device, and the slot number to which you wish
160to change. If the slot number is -1, the drive is unloaded.
161
162
1634. Compilation options
164----------------------
165
166There are a few additional options which can be set when compiling the
167driver. Most people should not need to mess with any of these; they
168are listed here simply for completeness. A compilation option can be
169enabled by adding a line of the form `#define <option> 1' to the top
170of ide-cd.c. All these options are disabled by default.
171
172VERBOSE_IDE_CD_ERRORS
173 If this is set, ATAPI error codes will be translated into textual
174 descriptions. In addition, a dump is made of the command which
175 provoked the error. This is off by default to save the memory used
176 by the (somewhat long) table of error descriptions.
177
178STANDARD_ATAPI
179 If this is set, the code needed to deal with certain drives which do
180 not properly implement the ATAPI spec will be disabled. If you know
181 your drive implements ATAPI properly, you can turn this on to get a
182 slightly smaller kernel.
183
184NO_DOOR_LOCKING
185 If this is set, the driver will never attempt to lock the door of
186 the drive.
187
188CDROM_NBLOCKS_BUFFER
189 This sets the size of the buffer to be used for a CDROMREADAUDIO
190 ioctl. The default is 8.
191
192TEST
193 This currently enables an additional ioctl which enables a user-mode
194 program to execute an arbitrary packet command. See the source for
195 details. This should be left off unless you know what you're doing.
196
197
1985. Common problems
199------------------
200
201This section discusses some common problems encountered when trying to
202use the driver, and some possible solutions. Note that if you are
203experiencing problems, you should probably also review
204Documentation/ide.txt for current information about the underlying
205IDE support code. Some of these items apply only to earlier versions
206of the driver, but are mentioned here for completeness.
207
208In most cases, you should probably check with `dmesg' for any errors
209from the driver.
210
211a. Drive is not detected during booting.
212
213 - Review the configuration instructions above and in
214 Documentation/ide.txt, and check how your hardware is
215 configured.
216
217 - If your drive is the only device on an IDE interface, it should
218 be jumpered as master, if at all possible.
219
220 - If your IDE interface is not at the standard addresses of 0x170
221 or 0x1f0, you'll need to explicitly inform the driver using a
222 lilo option. See Documentation/ide.txt. (This feature was
223 added around kernel version 1.3.30.)
224
225 - If the autoprobing is not finding your drive, you can tell the
226 driver to assume that one exists by using a lilo option of the
227 form `hdX=cdrom', where X is the drive letter corresponding to
228 where your drive is installed. Note that if you do this and you
229 see a boot message like
230
231 hdX: ATAPI cdrom (?)
232
233 this does _not_ mean that the driver has successfully detected
234 the drive; rather, it means that the driver has not detected a
235 drive, but is assuming there's one there anyway because you told
236 it so. If you actually try to do I/O to a drive defined at a
237 nonexistent or nonresponding I/O address, you'll probably get
238 errors with a status value of 0xff.
239
240 - Some IDE adapters require a nonstandard initialization sequence
241 before they'll function properly. (If this is the case, there
242 will often be a separate MS-DOS driver just for the controller.)
243 IDE interfaces on sound cards often fall into this category.
244
245 Support for some interfaces needing extra initialization is
246 provided in later 1.3.x kernels. You may need to turn on
247 additional kernel configuration options to get them to work;
248 see Documentation/ide.txt.
249
250 Even if support is not available for your interface, you may be
251 able to get it to work with the following procedure. First boot
252 MS-DOS and load the appropriate drivers. Then warm-boot linux
253 (i.e., without powering off). If this works, it can be automated
254 by running loadlin from the MS-DOS autoexec.
255
256
257b. Timeout/IRQ errors.
258
259 - If you always get timeout errors, interrupts from the drive are
260 probably not making it to the host.
261
262 - IRQ problems may also be indicated by the message
263 `IRQ probe failed (<n>)' while booting. If <n> is zero, that
264 means that the system did not see an interrupt from the drive when
265 it was expecting one (on any feasible IRQ). If <n> is negative,
266 that means the system saw interrupts on multiple IRQ lines, when
267 it was expecting to receive just one from the CDROM drive.
268
269 - Double-check your hardware configuration to make sure that the IRQ
270 number of your IDE interface matches what the driver expects.
271 (The usual assignments are 14 for the primary (0x1f0) interface
272 and 15 for the secondary (0x170) interface.) Also be sure that
273 you don't have some other hardware which might be conflicting with
274 the IRQ you're using. Also check the BIOS setup for your system;
275 some have the ability to disable individual IRQ levels, and I've
276 had one report of a system which was shipped with IRQ 15 disabled
277 by default.
278
279 - Note that many MS-DOS CDROM drivers will still function even if
280 there are hardware problems with the interrupt setup; they
281 apparently don't use interrupts.
282
283 - If you own a Pioneer DR-A24X, you _will_ get nasty error messages
284 on boot such as "irq timeout: status=0x50 { DriveReady SeekComplete }"
285 The Pioneer DR-A24X CDROM drives are fairly popular these days.
286 Unfortunately, these drives seem to become very confused when we perform
287 the standard Linux ATA disk drive probe. If you own one of these drives,
288 you can bypass the ATA probing which confuses these CDROM drives, by
289 adding `append="hdX=noprobe hdX=cdrom"' to your lilo.conf file and running
290 lilo (again where X is the drive letter corresponding to where your drive
291 is installed.)
292
293c. System hangups.
294
295 - If the system locks up when you try to access the CDROM, the most
296 likely cause is that you have a buggy IDE adapter which doesn't
297 properly handle simultaneous transactions on multiple interfaces.
298 The most notorious of these is the CMD640B chip. This problem can
299 be worked around by specifying the `serialize' option when
300 booting. Recent kernels should be able to detect the need for
301 this automatically in most cases, but the detection is not
302 foolproof. See Documentation/ide.txt for more information
303 about the `serialize' option and the CMD640B.
304
305 - Note that many MS-DOS CDROM drivers will work with such buggy
306 hardware, apparently because they never attempt to overlap CDROM
307 operations with other disk activity.
308
309
310d. Can't mount a CDROM.
311
312 - If you get errors from mount, it may help to check `dmesg' to see
313 if there are any more specific errors from the driver or from the
314 filesystem.
315
316 - Make sure there's a CDROM loaded in the drive, and that's it's an
317 ISO 9660 disc. You can't mount an audio CD.
318
319 - With the CDROM in the drive and unmounted, try something like
320
321 cat /dev/cdrom | od | more
322
323 If you see a dump, then the drive and driver are probably working
324 OK, and the problem is at the filesystem level (i.e., the CDROM is
325 not ISO 9660 or has errors in the filesystem structure).
326
327 - If you see `not a block device' errors, check that the definitions
328 of the device special files are correct. They should be as
329 follows:
330
331 brw-rw---- 1 root disk 3, 0 Nov 11 18:48 /dev/hda
332 brw-rw---- 1 root disk 3, 64 Nov 11 18:48 /dev/hdb
333 brw-rw---- 1 root disk 22, 0 Nov 11 18:48 /dev/hdc
334 brw-rw---- 1 root disk 22, 64 Nov 11 18:48 /dev/hdd
335
336 Some early Slackware releases had these defined incorrectly. If
337 these are wrong, you can remake them by running the script
338 scripts/MAKEDEV.ide. (You may have to make it executable
339 with chmod first.)
340
341 If you have a /dev/cdrom symbolic link, check that it is pointing
342 to the correct device file.
343
344 If you hear people talking of the devices `hd1a' and `hd1b', these
345 were old names for what are now called hdc and hdd. Those names
346 should be considered obsolete.
347
348 - If mount is complaining that the iso9660 filesystem is not
349 available, but you know it is (check /proc/filesystems), you
350 probably need a newer version of mount. Early versions would not
351 always give meaningful error messages.
352
353
354e. Directory listings are unpredictably truncated, and `dmesg' shows
355 `buffer botch' error messages from the driver.
356
357 - There was a bug in the version of the driver in 1.2.x kernels
358 which could cause this. It was fixed in 1.3.0. If you can't
359 upgrade, you can probably work around the problem by specifying a
360 blocksize of 2048 when mounting. (Note that you won't be able to
361 directly execute binaries off the CDROM in that case.)
362
363 If you see this in kernels later than 1.3.0, please report it as a
364 bug.
365
366
367f. Data corruption.
368
369 - Random data corruption was occasionally observed with the Hitachi
370 CDR-7730 CDROM. If you experience data corruption, using "hdx=slow"
371 as a command line parameter may work around the problem, at the
372 expense of low system performance.
373
374
3756. cdchange.c
376-------------
377
378/*
379 * cdchange.c [-v] <device> [<slot>]
380 *
381 * This loads a CDROM from a specified slot in a changer, and displays
382 * information about the changer status. The drive should be unmounted before
383 * using this program.
384 *
385 * Changer information is displayed if either the -v flag is specified
386 * or no slot was specified.
387 *
388 * Based on code originally from Gerhard Zuber <zuber@berlin.snafu.de>.
389 * Changer status information, and rewrite for the new Uniform CDROM driver
390 * interface by Erik Andersen <andersee@debian.org>.
391 */
392
393#include <stdio.h>
394#include <stdlib.h>
395#include <errno.h>
396#include <string.h>
397#include <unistd.h>
398#include <fcntl.h>
399#include <sys/ioctl.h>
400#include <linux/cdrom.h>
401
402
403int
404main (int argc, char **argv)
405{
406 char *program;
407 char *device;
408 int fd; /* file descriptor for CD-ROM device */
409 int status; /* return status for system calls */
410 int verbose = 0;
411 int slot=-1, x_slot;
412 int total_slots_available;
413
414 program = argv[0];
415
416 ++argv;
417 --argc;
418
419 if (argc < 1 || argc > 3) {
420 fprintf (stderr, "usage: %s [-v] <device> [<slot>]\n",
421 program);
422 fprintf (stderr, " Slots are numbered 1 -- n.\n");
423 exit (1);
424 }
425
426 if (strcmp (argv[0], "-v") == 0) {
427 verbose = 1;
428 ++argv;
429 --argc;
430 }
431
432 device = argv[0];
433
434 if (argc == 2)
435 slot = atoi (argv[1]) - 1;
436
437 /* open device */
438 fd = open(device, O_RDONLY | O_NONBLOCK);
439 if (fd < 0) {
440 fprintf (stderr, "%s: open failed for `%s': %s\n",
441 program, device, strerror (errno));
442 exit (1);
443 }
444
445 /* Check CD player status */
446 total_slots_available = ioctl (fd, CDROM_CHANGER_NSLOTS);
447 if (total_slots_available <= 1 ) {
448 fprintf (stderr, "%s: Device `%s' is not an ATAPI "
449 "compliant CD changer.\n", program, device);
450 exit (1);
451 }
452
453 if (slot >= 0) {
454 if (slot >= total_slots_available) {
455 fprintf (stderr, "Bad slot number. "
456 "Should be 1 -- %d.\n",
457 total_slots_available);
458 exit (1);
459 }
460
461 /* load */
462 slot=ioctl (fd, CDROM_SELECT_DISC, slot);
463 if (slot<0) {
464 fflush(stdout);
465 perror ("CDROM_SELECT_DISC ");
466 exit(1);
467 }
468 }
469
470 if (slot < 0 || verbose) {
471
472 status=ioctl (fd, CDROM_SELECT_DISC, CDSL_CURRENT);
473 if (status<0) {
474 fflush(stdout);
475 perror (" CDROM_SELECT_DISC");
476 exit(1);
477 }
478 slot=status;
479
480 printf ("Current slot: %d\n", slot+1);
481 printf ("Total slots available: %d\n",
482 total_slots_available);
483
484 printf ("Drive status: ");
485 status = ioctl (fd, CDROM_DRIVE_STATUS, CDSL_CURRENT);
486 if (status<0) {
487 perror(" CDROM_DRIVE_STATUS");
488 } else switch(status) {
489 case CDS_DISC_OK:
490 printf ("Ready.\n");
491 break;
492 case CDS_TRAY_OPEN:
493 printf ("Tray Open.\n");
494 break;
495 case CDS_DRIVE_NOT_READY:
496 printf ("Drive Not Ready.\n");
497 break;
498 default:
499 printf ("This Should not happen!\n");
500 break;
501 }
502
503 for (x_slot=0; x_slot<total_slots_available; x_slot++) {
504 printf ("Slot %2d: ", x_slot+1);
505 status = ioctl (fd, CDROM_DRIVE_STATUS, x_slot);
506 if (status<0) {
507 perror(" CDROM_DRIVE_STATUS");
508 } else switch(status) {
509 case CDS_DISC_OK:
510 printf ("Disc present.");
511 break;
512 case CDS_NO_DISC:
513 printf ("Empty slot.");
514 break;
515 case CDS_TRAY_OPEN:
516 printf ("CD-ROM tray open.\n");
517 break;
518 case CDS_DRIVE_NOT_READY:
519 printf ("CD-ROM drive not ready.\n");
520 break;
521 case CDS_NO_INFO:
522 printf ("No Information available.");
523 break;
524 default:
525 printf ("This Should not happen!\n");
526 break;
527 }
528 if (slot == x_slot) {
529 status = ioctl (fd, CDROM_DISC_STATUS);
530 if (status<0) {
531 perror(" CDROM_DISC_STATUS");
532 }
533 switch (status) {
534 case CDS_AUDIO:
535 printf ("\tAudio disc.\t");
536 break;
537 case CDS_DATA_1:
538 case CDS_DATA_2:
539 printf ("\tData disc type %d.\t", status-CDS_DATA_1+1);
540 break;
541 case CDS_XA_2_1:
542 case CDS_XA_2_2:
543 printf ("\tXA data disc type %d.\t", status-CDS_XA_2_1+1);
544 break;
545 default:
546 printf ("\tUnknown disc type 0x%x!\t", status);
547 break;
548 }
549 }
550 status = ioctl (fd, CDROM_MEDIA_CHANGED, x_slot);
551 if (status<0) {
552 perror(" CDROM_MEDIA_CHANGED");
553 }
554 switch (status) {
555 case 1:
556 printf ("Changed.\n");
557 break;
558 default:
559 printf ("\n");
560 break;
561 }
562 }
563 }
564
565 /* close device */
566 status = close (fd);
567 if (status != 0) {
568 fprintf (stderr, "%s: close failed for `%s': %s\n",
569 program, device, strerror (errno));
570 exit (1);
571 }
572
573 exit (0);
574}