linux/Documentation/cdrom/ide-cd.rst
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   1IDE-CD driver documentation
   2===========================
   3
   4:Originally by: scott snyder  <snyder@fnald0.fnal.gov> (19 May 1996)
   5:Carrying on the torch is: Erik Andersen <andersee@debian.org>
   6:New maintainers (19 Oct 1998): Jens Axboe <axboe@image.dk>
   7
   81. Introduction
   9---------------
  10
  11The ide-cd driver should work with all ATAPI ver 1.2 to ATAPI 2.6 compliant
  12CDROM drives which attach to an IDE interface.  Note that some CDROM vendors
  13(including Mitsumi, Sony, Creative, Aztech, and Goldstar) have made
  14both ATAPI-compliant drives and drives which use a proprietary
  15interface.  If your drive uses one of those proprietary interfaces,
  16this driver will not work with it (but one of the other CDROM drivers
  17probably will).  This driver will not work with `ATAPI` drives which
  18attach to the parallel port.  In addition, there is at least one drive
  19(CyCDROM CR520ie) which attaches to the IDE port but is not ATAPI;
  20this driver will not work with drives like that either (but see the
  21aztcd driver).
  22
  23This driver provides the following features:
  24
  25 - Reading from data tracks, and mounting ISO 9660 filesystems.
  26
  27 - Playing audio tracks.  Most of the CDROM player programs floating
  28   around should work; I usually use Workman.
  29
  30 - Multisession support.
  31
  32 - On drives which support it, reading digital audio data directly
  33   from audio tracks.  The program cdda2wav can be used for this.
  34   Note, however, that only some drives actually support this.
  35
  36 - There is now support for CDROM changers which comply with the
  37   ATAPI 2.6 draft standard (such as the NEC CDR-251).  This additional
  38   functionality includes a function call to query which slot is the
  39   currently selected slot, a function call to query which slots contain
  40   CDs, etc. A sample program which demonstrates this functionality is
  41   appended to the end of this file.  The Sanyo 3-disc changer
  42   (which does not conform to the standard) is also now supported.
  43   Please note the driver refers to the first CD as slot # 0.
  44
  45
  462. Installation
  47---------------
  48
  490. The ide-cd relies on the ide disk driver.  See
  50   Documentation/ide/ide.rst for up-to-date information on the ide
  51   driver.
  52
  531. Make sure that the ide and ide-cd drivers are compiled into the
  54   kernel you're using.  When configuring the kernel, in the section
  55   entitled "Floppy, IDE, and other block devices", say either `Y`
  56   (which will compile the support directly into the kernel) or `M`
  57   (to compile support as a module which can be loaded and unloaded)
  58   to the options::
  59
  60      ATA/ATAPI/MFM/RLL support
  61      Include IDE/ATAPI CDROM support
  62
  63   Depending on what type of IDE interface you have, you may need to
  64   specify additional configuration options.  See
  65   Documentation/ide/ide.rst.
  66
  672. You should also ensure that the iso9660 filesystem is either
  68   compiled into the kernel or available as a loadable module.  You
  69   can see if a filesystem is known to the kernel by catting
  70   /proc/filesystems.
  71
  723. The CDROM drive should be connected to the host on an IDE
  73   interface.  Each interface on a system is defined by an I/O port
  74   address and an IRQ number, the standard assignments being
  75   0x1f0 and 14 for the primary interface and 0x170 and 15 for the
  76   secondary interface.  Each interface can control up to two devices,
  77   where each device can be a hard drive, a CDROM drive, a floppy drive,
  78   or a tape drive.  The two devices on an interface are called `master`
  79   and `slave`; this is usually selectable via a jumper on the drive.
  80
  81   Linux names these devices as follows.  The master and slave devices
  82   on the primary IDE interface are called `hda` and `hdb`,
  83   respectively.  The drives on the secondary interface are called
  84   `hdc` and `hdd`.  (Interfaces at other locations get other letters
  85   in the third position; see Documentation/ide/ide.rst.)
  86
  87   If you want your CDROM drive to be found automatically by the
  88   driver, you should make sure your IDE interface uses either the
  89   primary or secondary addresses mentioned above.  In addition, if
  90   the CDROM drive is the only device on the IDE interface, it should
  91   be jumpered as `master`.  (If for some reason you cannot configure
  92   your system in this manner, you can probably still use the driver.
  93   You may have to pass extra configuration information to the kernel
  94   when you boot, however.  See Documentation/ide/ide.rst for more
  95   information.)
  96
  974. Boot the system.  If the drive is recognized, you should see a
  98   message which looks like::
  99
 100     hdb: NEC CD-ROM DRIVE:260, ATAPI CDROM drive
 101
 102   If you do not see this, see section 5 below.
 103
 1045. You may want to create a symbolic link /dev/cdrom pointing to the
 105   actual device.  You can do this with the command::
 106
 107     ln -s  /dev/hdX  /dev/cdrom
 108
 109   where X should be replaced by the letter indicating where your
 110   drive is installed.
 111
 1126. You should be able to see any error messages from the driver with
 113   the `dmesg` command.
 114
 115
 1163. Basic usage
 117--------------
 118
 119An ISO 9660 CDROM can be mounted by putting the disc in the drive and
 120typing (as root)::
 121
 122  mount -t iso9660 /dev/cdrom /mnt/cdrom
 123
 124where it is assumed that /dev/cdrom is a link pointing to the actual
 125device (as described in step 5 of the last section) and /mnt/cdrom is
 126an empty directory.  You should now be able to see the contents of the
 127CDROM under the /mnt/cdrom directory.  If you want to eject the CDROM,
 128you must first dismount it with a command like::
 129
 130  umount /mnt/cdrom
 131
 132Note that audio CDs cannot be mounted.
 133
 134Some distributions set up /etc/fstab to always try to mount a CDROM
 135filesystem on bootup.  It is not required to mount the CDROM in this
 136manner, though, and it may be a nuisance if you change CDROMs often.
 137You should feel free to remove the cdrom line from /etc/fstab and
 138mount CDROMs manually if that suits you better.
 139
 140Multisession and photocd discs should work with no special handling.
 141The hpcdtoppm package (ftp.gwdg.de:/pub/linux/hpcdtoppm/) may be
 142useful for reading photocds.
 143
 144To play an audio CD, you should first unmount and remove any data
 145CDROM.  Any of the CDROM player programs should then work (workman,
 146workbone, cdplayer, etc.).
 147
 148On a few drives, you can read digital audio directly using a program
 149such as cdda2wav.  The only types of drive which I've heard support
 150this are Sony and Toshiba drives.  You will get errors if you try to
 151use this function on a drive which does not support it.
 152
 153For supported changers, you can use the `cdchange` program (appended to
 154the end of this file) to switch between changer slots.  Note that the
 155drive should be unmounted before attempting this.  The program takes
 156two arguments:  the CDROM device, and the slot number to which you wish
 157to change.  If the slot number is -1, the drive is unloaded.
 158
 159
 1604. Common problems
 161------------------
 162
 163This section discusses some common problems encountered when trying to
 164use the driver, and some possible solutions.  Note that if you are
 165experiencing problems, you should probably also review
 166Documentation/ide/ide.rst for current information about the underlying
 167IDE support code.  Some of these items apply only to earlier versions
 168of the driver, but are mentioned here for completeness.
 169
 170In most cases, you should probably check with `dmesg` for any errors
 171from the driver.
 172
 173a. Drive is not detected during booting.
 174
 175   - Review the configuration instructions above and in
 176     Documentation/ide/ide.rst, and check how your hardware is
 177     configured.
 178
 179   - If your drive is the only device on an IDE interface, it should
 180     be jumpered as master, if at all possible.
 181
 182   - If your IDE interface is not at the standard addresses of 0x170
 183     or 0x1f0, you'll need to explicitly inform the driver using a
 184     lilo option.  See Documentation/ide/ide.rst.  (This feature was
 185     added around kernel version 1.3.30.)
 186
 187   - If the autoprobing is not finding your drive, you can tell the
 188     driver to assume that one exists by using a lilo option of the
 189     form `hdX=cdrom`, where X is the drive letter corresponding to
 190     where your drive is installed.  Note that if you do this and you
 191     see a boot message like::
 192
 193       hdX: ATAPI cdrom (?)
 194
 195     this does _not_ mean that the driver has successfully detected
 196     the drive; rather, it means that the driver has not detected a
 197     drive, but is assuming there's one there anyway because you told
 198     it so.  If you actually try to do I/O to a drive defined at a
 199     nonexistent or nonresponding I/O address, you'll probably get
 200     errors with a status value of 0xff.
 201
 202   - Some IDE adapters require a nonstandard initialization sequence
 203     before they'll function properly.  (If this is the case, there
 204     will often be a separate MS-DOS driver just for the controller.)
 205     IDE interfaces on sound cards often fall into this category.
 206
 207     Support for some interfaces needing extra initialization is
 208     provided in later 1.3.x kernels.  You may need to turn on
 209     additional kernel configuration options to get them to work;
 210     see Documentation/ide/ide.rst.
 211
 212     Even if support is not available for your interface, you may be
 213     able to get it to work with the following procedure.  First boot
 214     MS-DOS and load the appropriate drivers.  Then warm-boot linux
 215     (i.e., without powering off).  If this works, it can be automated
 216     by running loadlin from the MS-DOS autoexec.
 217
 218
 219b. Timeout/IRQ errors.
 220
 221  - If you always get timeout errors, interrupts from the drive are
 222    probably not making it to the host.
 223
 224  - IRQ problems may also be indicated by the message
 225    `IRQ probe failed (<n>)` while booting.  If <n> is zero, that
 226    means that the system did not see an interrupt from the drive when
 227    it was expecting one (on any feasible IRQ).  If <n> is negative,
 228    that means the system saw interrupts on multiple IRQ lines, when
 229    it was expecting to receive just one from the CDROM drive.
 230
 231  - Double-check your hardware configuration to make sure that the IRQ
 232    number of your IDE interface matches what the driver expects.
 233    (The usual assignments are 14 for the primary (0x1f0) interface
 234    and 15 for the secondary (0x170) interface.)  Also be sure that
 235    you don't have some other hardware which might be conflicting with
 236    the IRQ you're using.  Also check the BIOS setup for your system;
 237    some have the ability to disable individual IRQ levels, and I've
 238    had one report of a system which was shipped with IRQ 15 disabled
 239    by default.
 240
 241  - Note that many MS-DOS CDROM drivers will still function even if
 242    there are hardware problems with the interrupt setup; they
 243    apparently don't use interrupts.
 244
 245  - If you own a Pioneer DR-A24X, you _will_ get nasty error messages
 246    on boot such as "irq timeout: status=0x50 { DriveReady SeekComplete }"
 247    The Pioneer DR-A24X CDROM drives are fairly popular these days.
 248    Unfortunately, these drives seem to become very confused when we perform
 249    the standard Linux ATA disk drive probe. If you own one of these drives,
 250    you can bypass the ATA probing which confuses these CDROM drives, by
 251    adding `append="hdX=noprobe hdX=cdrom"` to your lilo.conf file and running
 252    lilo (again where X is the drive letter corresponding to where your drive
 253    is installed.)
 254
 255c. System hangups.
 256
 257  - If the system locks up when you try to access the CDROM, the most
 258    likely cause is that you have a buggy IDE adapter which doesn't
 259    properly handle simultaneous transactions on multiple interfaces.
 260    The most notorious of these is the CMD640B chip.  This problem can
 261    be worked around by specifying the `serialize` option when
 262    booting.  Recent kernels should be able to detect the need for
 263    this automatically in most cases, but the detection is not
 264    foolproof.  See Documentation/ide/ide.rst for more information
 265    about the `serialize` option and the CMD640B.
 266
 267  - Note that many MS-DOS CDROM drivers will work with such buggy
 268    hardware, apparently because they never attempt to overlap CDROM
 269    operations with other disk activity.
 270
 271
 272d. Can't mount a CDROM.
 273
 274  - If you get errors from mount, it may help to check `dmesg` to see
 275    if there are any more specific errors from the driver or from the
 276    filesystem.
 277
 278  - Make sure there's a CDROM loaded in the drive, and that's it's an
 279    ISO 9660 disc.  You can't mount an audio CD.
 280
 281  - With the CDROM in the drive and unmounted, try something like::
 282
 283      cat /dev/cdrom | od | more
 284
 285    If you see a dump, then the drive and driver are probably working
 286    OK, and the problem is at the filesystem level (i.e., the CDROM is
 287    not ISO 9660 or has errors in the filesystem structure).
 288
 289  - If you see `not a block device` errors, check that the definitions
 290    of the device special files are correct.  They should be as
 291    follows::
 292
 293      brw-rw----   1 root     disk       3,   0 Nov 11 18:48 /dev/hda
 294      brw-rw----   1 root     disk       3,  64 Nov 11 18:48 /dev/hdb
 295      brw-rw----   1 root     disk      22,   0 Nov 11 18:48 /dev/hdc
 296      brw-rw----   1 root     disk      22,  64 Nov 11 18:48 /dev/hdd
 297
 298    Some early Slackware releases had these defined incorrectly.  If
 299    these are wrong, you can remake them by running the script
 300    scripts/MAKEDEV.ide.  (You may have to make it executable
 301    with chmod first.)
 302
 303    If you have a /dev/cdrom symbolic link, check that it is pointing
 304    to the correct device file.
 305
 306    If you hear people talking of the devices `hd1a` and `hd1b`, these
 307    were old names for what are now called hdc and hdd.  Those names
 308    should be considered obsolete.
 309
 310  - If mount is complaining that the iso9660 filesystem is not
 311    available, but you know it is (check /proc/filesystems), you
 312    probably need a newer version of mount.  Early versions would not
 313    always give meaningful error messages.
 314
 315
 316e. Directory listings are unpredictably truncated, and `dmesg` shows
 317   `buffer botch` error messages from the driver.
 318
 319  - There was a bug in the version of the driver in 1.2.x kernels
 320    which could cause this.  It was fixed in 1.3.0.  If you can't
 321    upgrade, you can probably work around the problem by specifying a
 322    blocksize of 2048 when mounting.  (Note that you won't be able to
 323    directly execute binaries off the CDROM in that case.)
 324
 325    If you see this in kernels later than 1.3.0, please report it as a
 326    bug.
 327
 328
 329f. Data corruption.
 330
 331  - Random data corruption was occasionally observed with the Hitachi
 332    CDR-7730 CDROM. If you experience data corruption, using "hdx=slow"
 333    as a command line parameter may work around the problem, at the
 334    expense of low system performance.
 335
 336
 3375. cdchange.c
 338-------------
 339
 340::
 341
 342  /*
 343   * cdchange.c  [-v]  <device>  [<slot>]
 344   *
 345   * This loads a CDROM from a specified slot in a changer, and displays
 346   * information about the changer status.  The drive should be unmounted before
 347   * using this program.
 348   *
 349   * Changer information is displayed if either the -v flag is specified
 350   * or no slot was specified.
 351   *
 352   * Based on code originally from Gerhard Zuber <zuber@berlin.snafu.de>.
 353   * Changer status information, and rewrite for the new Uniform CDROM driver
 354   * interface by Erik Andersen <andersee@debian.org>.
 355   */
 356
 357  #include <stdio.h>
 358  #include <stdlib.h>
 359  #include <errno.h>
 360  #include <string.h>
 361  #include <unistd.h>
 362  #include <fcntl.h>
 363  #include <sys/ioctl.h>
 364  #include <linux/cdrom.h>
 365
 366
 367  int
 368  main (int argc, char **argv)
 369  {
 370        char *program;
 371        char *device;
 372        int fd;           /* file descriptor for CD-ROM device */
 373        int status;       /* return status for system calls */
 374        int verbose = 0;
 375        int slot=-1, x_slot;
 376        int total_slots_available;
 377
 378        program = argv[0];
 379
 380        ++argv;
 381        --argc;
 382
 383        if (argc < 1 || argc > 3) {
 384                fprintf (stderr, "usage: %s [-v] <device> [<slot>]\n",
 385                         program);
 386                fprintf (stderr, "       Slots are numbered 1 -- n.\n");
 387                exit (1);
 388        }
 389
 390       if (strcmp (argv[0], "-v") == 0) {
 391                verbose = 1;
 392                ++argv;
 393                --argc;
 394        }
 395
 396        device = argv[0];
 397
 398        if (argc == 2)
 399                slot = atoi (argv[1]) - 1;
 400
 401        /* open device */
 402        fd = open(device, O_RDONLY | O_NONBLOCK);
 403        if (fd < 0) {
 404                fprintf (stderr, "%s: open failed for `%s`: %s\n",
 405                         program, device, strerror (errno));
 406                exit (1);
 407        }
 408
 409        /* Check CD player status */
 410        total_slots_available = ioctl (fd, CDROM_CHANGER_NSLOTS);
 411        if (total_slots_available <= 1 ) {
 412                fprintf (stderr, "%s: Device `%s` is not an ATAPI "
 413                        "compliant CD changer.\n", program, device);
 414                exit (1);
 415        }
 416
 417        if (slot >= 0) {
 418                if (slot >= total_slots_available) {
 419                        fprintf (stderr, "Bad slot number.  "
 420                                 "Should be 1 -- %d.\n",
 421                                 total_slots_available);
 422                        exit (1);
 423                }
 424
 425                /* load */
 426                slot=ioctl (fd, CDROM_SELECT_DISC, slot);
 427                if (slot<0) {
 428                        fflush(stdout);
 429                                perror ("CDROM_SELECT_DISC ");
 430                        exit(1);
 431                }
 432        }
 433
 434        if (slot < 0 || verbose) {
 435
 436                status=ioctl (fd, CDROM_SELECT_DISC, CDSL_CURRENT);
 437                if (status<0) {
 438                        fflush(stdout);
 439                        perror (" CDROM_SELECT_DISC");
 440                        exit(1);
 441                }
 442                slot=status;
 443
 444                printf ("Current slot: %d\n", slot+1);
 445                printf ("Total slots available: %d\n",
 446                        total_slots_available);
 447
 448                printf ("Drive status: ");
 449                status = ioctl (fd, CDROM_DRIVE_STATUS, CDSL_CURRENT);
 450                if (status<0) {
 451                  perror(" CDROM_DRIVE_STATUS");
 452                } else switch(status) {
 453                case CDS_DISC_OK:
 454                        printf ("Ready.\n");
 455                        break;
 456                case CDS_TRAY_OPEN:
 457                        printf ("Tray Open.\n");
 458                        break;
 459                case CDS_DRIVE_NOT_READY:
 460                        printf ("Drive Not Ready.\n");
 461                        break;
 462                default:
 463                        printf ("This Should not happen!\n");
 464                        break;
 465                }
 466
 467                for (x_slot=0; x_slot<total_slots_available; x_slot++) {
 468                        printf ("Slot %2d: ", x_slot+1);
 469                        status = ioctl (fd, CDROM_DRIVE_STATUS, x_slot);
 470                        if (status<0) {
 471                             perror(" CDROM_DRIVE_STATUS");
 472                        } else switch(status) {
 473                        case CDS_DISC_OK:
 474                                printf ("Disc present.");
 475                                break;
 476                        case CDS_NO_DISC:
 477                                printf ("Empty slot.");
 478                                break;
 479                        case CDS_TRAY_OPEN:
 480                                printf ("CD-ROM tray open.\n");
 481                                break;
 482                        case CDS_DRIVE_NOT_READY:
 483                                printf ("CD-ROM drive not ready.\n");
 484                                break;
 485                        case CDS_NO_INFO:
 486                                printf ("No Information available.");
 487                                break;
 488                        default:
 489                                printf ("This Should not happen!\n");
 490                                break;
 491                        }
 492                  if (slot == x_slot) {
 493                  status = ioctl (fd, CDROM_DISC_STATUS);
 494                  if (status<0) {
 495                        perror(" CDROM_DISC_STATUS");
 496                  }
 497                  switch (status) {
 498                        case CDS_AUDIO:
 499                                printf ("\tAudio disc.\t");
 500                                break;
 501                        case CDS_DATA_1:
 502                        case CDS_DATA_2:
 503                                printf ("\tData disc type %d.\t", status-CDS_DATA_1+1);
 504                                break;
 505                        case CDS_XA_2_1:
 506                        case CDS_XA_2_2:
 507                                printf ("\tXA data disc type %d.\t", status-CDS_XA_2_1+1);
 508                                break;
 509                        default:
 510                                printf ("\tUnknown disc type 0x%x!\t", status);
 511                                break;
 512                        }
 513                        }
 514                        status = ioctl (fd, CDROM_MEDIA_CHANGED, x_slot);
 515                        if (status<0) {
 516                                perror(" CDROM_MEDIA_CHANGED");
 517                        }
 518                        switch (status) {
 519                        case 1:
 520                                printf ("Changed.\n");
 521                                break;
 522                        default:
 523                                printf ("\n");
 524                                break;
 525                        }
 526                }
 527        }
 528
 529        /* close device */
 530        status = close (fd);
 531        if (status != 0) {
 532                fprintf (stderr, "%s: close failed for `%s`: %s\n",
 533                         program, device, strerror (errno));
 534                exit (1);
 535        }
 536
 537        exit (0);
 538  }
 539