linux/Documentation/cdrom/ide-cd
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   1IDE-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/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/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/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/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.).
 149
 150On a few drives, you can read digital audio directly using a program
 151such as cdda2wav.  The only types of drive which I've heard support
 152this are Sony and Toshiba drives.  You will get errors if you try to
 153use this function on a drive which does not support it.
 154
 155For supported changers, you can use the `cdchange' program (appended to
 156the end of this file) to switch between changer slots.  Note that the
 157drive should be unmounted before attempting this.  The program takes
 158two arguments:  the CDROM device, and the slot number to which you wish
 159to change.  If the slot number is -1, the drive is unloaded.
 160
 161
 1624. Common problems
 163------------------
 164
 165This section discusses some common problems encountered when trying to
 166use the driver, and some possible solutions.  Note that if you are
 167experiencing problems, you should probably also review
 168Documentation/ide/ide.txt for current information about the underlying
 169IDE support code.  Some of these items apply only to earlier versions
 170of the driver, but are mentioned here for completeness.
 171
 172In most cases, you should probably check with `dmesg' for any errors
 173from the driver.
 174
 175a. Drive is not detected during booting.
 176
 177   - Review the configuration instructions above and in
 178     Documentation/ide/ide.txt, and check how your hardware is
 179     configured.
 180
 181   - If your drive is the only device on an IDE interface, it should
 182     be jumpered as master, if at all possible.
 183
 184   - If your IDE interface is not at the standard addresses of 0x170
 185     or 0x1f0, you'll need to explicitly inform the driver using a
 186     lilo option.  See Documentation/ide/ide.txt.  (This feature was
 187     added around kernel version 1.3.30.)
 188
 189   - If the autoprobing is not finding your drive, you can tell the
 190     driver to assume that one exists by using a lilo option of the
 191     form `hdX=cdrom', where X is the drive letter corresponding to
 192     where your drive is installed.  Note that if you do this and you 
 193     see a boot message like
 194
 195       hdX: ATAPI cdrom (?)
 196
 197     this does _not_ mean that the driver has successfully detected
 198     the drive; rather, it means that the driver has not detected a
 199     drive, but is assuming there's one there anyway because you told
 200     it so.  If you actually try to do I/O to a drive defined at a
 201     nonexistent or nonresponding I/O address, you'll probably get
 202     errors with a status value of 0xff.
 203
 204   - Some IDE adapters require a nonstandard initialization sequence
 205     before they'll function properly.  (If this is the case, there
 206     will often be a separate MS-DOS driver just for the controller.)
 207     IDE interfaces on sound cards often fall into this category.
 208
 209     Support for some interfaces needing extra initialization is
 210     provided in later 1.3.x kernels.  You may need to turn on
 211     additional kernel configuration options to get them to work;
 212     see Documentation/ide/ide.txt.
 213
 214     Even if support is not available for your interface, you may be
 215     able to get it to work with the following procedure.  First boot
 216     MS-DOS and load the appropriate drivers.  Then warm-boot linux
 217     (i.e., without powering off).  If this works, it can be automated
 218     by running loadlin from the MS-DOS autoexec.
 219
 220
 221b. Timeout/IRQ errors.
 222
 223  - If you always get timeout errors, interrupts from the drive are
 224    probably not making it to the host.
 225
 226  - IRQ problems may also be indicated by the message
 227    `IRQ probe failed (<n>)' while booting.  If <n> is zero, that
 228    means that the system did not see an interrupt from the drive when
 229    it was expecting one (on any feasible IRQ).  If <n> is negative,
 230    that means the system saw interrupts on multiple IRQ lines, when
 231    it was expecting to receive just one from the CDROM drive.
 232
 233  - Double-check your hardware configuration to make sure that the IRQ
 234    number of your IDE interface matches what the driver expects.
 235    (The usual assignments are 14 for the primary (0x1f0) interface
 236    and 15 for the secondary (0x170) interface.)  Also be sure that
 237    you don't have some other hardware which might be conflicting with
 238    the IRQ you're using.  Also check the BIOS setup for your system;
 239    some have the ability to disable individual IRQ levels, and I've
 240    had one report of a system which was shipped with IRQ 15 disabled
 241    by default.
 242
 243  - Note that many MS-DOS CDROM drivers will still function even if
 244    there are hardware problems with the interrupt setup; they
 245    apparently don't use interrupts.
 246
 247  - If you own a Pioneer DR-A24X, you _will_ get nasty error messages 
 248    on boot such as "irq timeout: status=0x50 { DriveReady SeekComplete }"
 249    The Pioneer DR-A24X CDROM drives are fairly popular these days.
 250    Unfortunately, these drives seem to become very confused when we perform
 251    the standard Linux ATA disk drive probe. If you own one of these drives,
 252    you can bypass the ATA probing which confuses these CDROM drives, by 
 253    adding `append="hdX=noprobe hdX=cdrom"' to your lilo.conf file and running 
 254    lilo (again where X is the drive letter corresponding to where your drive 
 255    is installed.)
 256    
 257c. System hangups.
 258
 259  - If the system locks up when you try to access the CDROM, the most
 260    likely cause is that you have a buggy IDE adapter which doesn't
 261    properly handle simultaneous transactions on multiple interfaces.
 262    The most notorious of these is the CMD640B chip.  This problem can
 263    be worked around by specifying the `serialize' option when
 264    booting.  Recent kernels should be able to detect the need for
 265    this automatically in most cases, but the detection is not
 266    foolproof.  See Documentation/ide/ide.txt for more information
 267    about the `serialize' option and the CMD640B.
 268
 269  - Note that many MS-DOS CDROM drivers will work with such buggy
 270    hardware, apparently because they never attempt to overlap CDROM
 271    operations with other disk activity.
 272
 273
 274d. Can't mount a CDROM.
 275
 276  - If you get errors from mount, it may help to check `dmesg' to see
 277    if there are any more specific errors from the driver or from the
 278    filesystem.
 279
 280  - Make sure there's a CDROM loaded in the drive, and that's it's an
 281    ISO 9660 disc.  You can't mount an audio CD.
 282
 283  - With the CDROM in the drive and unmounted, try something like
 284
 285      cat /dev/cdrom | od | more
 286
 287    If you see a dump, then the drive and driver are probably working
 288    OK, and the problem is at the filesystem level (i.e., the CDROM is
 289    not ISO 9660 or has errors in the filesystem structure).
 290
 291  - If you see `not a block device' errors, check that the definitions
 292    of the device special files are correct.  They should be as
 293    follows:
 294
 295      brw-rw----   1 root     disk       3,   0 Nov 11 18:48 /dev/hda
 296      brw-rw----   1 root     disk       3,  64 Nov 11 18:48 /dev/hdb
 297      brw-rw----   1 root     disk      22,   0 Nov 11 18:48 /dev/hdc
 298      brw-rw----   1 root     disk      22,  64 Nov 11 18:48 /dev/hdd
 299
 300    Some early Slackware releases had these defined incorrectly.  If
 301    these are wrong, you can remake them by running the script
 302    scripts/MAKEDEV.ide.  (You may have to make it executable
 303    with chmod first.)
 304
 305    If you have a /dev/cdrom symbolic link, check that it is pointing
 306    to the correct device file.
 307
 308    If you hear people talking of the devices `hd1a' and `hd1b', these
 309    were old names for what are now called hdc and hdd.  Those names
 310    should be considered obsolete.
 311
 312  - If mount is complaining that the iso9660 filesystem is not
 313    available, but you know it is (check /proc/filesystems), you
 314    probably need a newer version of mount.  Early versions would not
 315    always give meaningful error messages.
 316
 317
 318e. Directory listings are unpredictably truncated, and `dmesg' shows
 319   `buffer botch' error messages from the driver.
 320
 321  - There was a bug in the version of the driver in 1.2.x kernels
 322    which could cause this.  It was fixed in 1.3.0.  If you can't
 323    upgrade, you can probably work around the problem by specifying a
 324    blocksize of 2048 when mounting.  (Note that you won't be able to
 325    directly execute binaries off the CDROM in that case.)
 326
 327    If you see this in kernels later than 1.3.0, please report it as a
 328    bug.
 329
 330
 331f. Data corruption.
 332
 333  - Random data corruption was occasionally observed with the Hitachi
 334    CDR-7730 CDROM. If you experience data corruption, using "hdx=slow"
 335    as a command line parameter may work around the problem, at the
 336    expense of low system performance.
 337
 338
 3395. cdchange.c
 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
 367int
 368main (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
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