--- /dev/null
+IDE-CD driver documentation
+Originally by scott snyder <snyder@fnald0.fnal.gov> (19 May 1996)
+Carrying on the torch is: Erik Andersen <andersee@debian.org>
+New maintainers (19 Oct 1998): Jens Axboe <axboe@image.dk>
+
+1. Introduction
+---------------
+
+The ide-cd driver should work with all ATAPI ver 1.2 to ATAPI 2.6 compliant
+CDROM drives which attach to an IDE interface. Note that some CDROM vendors
+(including Mitsumi, Sony, Creative, Aztech, and Goldstar) have made
+both ATAPI-compliant drives and drives which use a proprietary
+interface. If your drive uses one of those proprietary interfaces,
+this driver will not work with it (but one of the other CDROM drivers
+probably will). This driver will not work with `ATAPI' drives which
+attach to the parallel port. In addition, there is at least one drive
+(CyCDROM CR520ie) which attaches to the IDE port but is not ATAPI;
+this driver will not work with drives like that either (but see the
+aztcd driver).
+
+This driver provides the following features:
+
+ - Reading from data tracks, and mounting ISO 9660 filesystems.
+
+ - Playing audio tracks. Most of the CDROM player programs floating
+ around should work; I usually use Workman.
+
+ - Multisession support.
+
+ - On drives which support it, reading digital audio data directly
+ from audio tracks. The program cdda2wav can be used for this.
+ Note, however, that only some drives actually support this.
+
+ - There is now support for CDROM changers which comply with the
+ ATAPI 2.6 draft standard (such as the NEC CDR-251). This additional
+ functionality includes a function call to query which slot is the
+ currently selected slot, a function call to query which slots contain
+ CDs, etc. A sample program which demonstrates this functionality is
+ appended to the end of this file. The Sanyo 3-disc changer
+ (which does not conform to the standard) is also now supported.
+ Please note the driver refers to the first CD as slot # 0.
+
+
+2. Installation
+---------------
+
+0. The ide-cd relies on the ide disk driver. See
+ Documentation/ide/ide.txt for up-to-date information on the ide
+ driver.
+
+1. Make sure that the ide and ide-cd drivers are compiled into the
+ kernel you're using. When configuring the kernel, in the section
+ entitled "Floppy, IDE, and other block devices", say either `Y'
+ (which will compile the support directly into the kernel) or `M'
+ (to compile support as a module which can be loaded and unloaded)
+ to the options:
+
+ Enhanced IDE/MFM/RLL disk/cdrom/tape/floppy support
+ Include IDE/ATAPI CDROM support
+
+ and `no' to
+
+ Use old disk-only driver on primary interface
+
+ Depending on what type of IDE interface you have, you may need to
+ specify additional configuration options. See
+ Documentation/ide/ide.txt.
+
+2. You should also ensure that the iso9660 filesystem is either
+ compiled into the kernel or available as a loadable module. You
+ can see if a filesystem is known to the kernel by catting
+ /proc/filesystems.
+
+3. The CDROM drive should be connected to the host on an IDE
+ interface. Each interface on a system is defined by an I/O port
+ address and an IRQ number, the standard assignments being
+ 0x1f0 and 14 for the primary interface and 0x170 and 15 for the
+ secondary interface. Each interface can control up to two devices,
+ where each device can be a hard drive, a CDROM drive, a floppy drive,
+ or a tape drive. The two devices on an interface are called `master'
+ and `slave'; this is usually selectable via a jumper on the drive.
+
+ Linux names these devices as follows. The master and slave devices
+ on the primary IDE interface are called `hda' and `hdb',
+ respectively. The drives on the secondary interface are called
+ `hdc' and `hdd'. (Interfaces at other locations get other letters
+ in the third position; see Documentation/ide/ide.txt.)
+
+ If you want your CDROM drive to be found automatically by the
+ driver, you should make sure your IDE interface uses either the
+ primary or secondary addresses mentioned above. In addition, if
+ the CDROM drive is the only device on the IDE interface, it should
+ be jumpered as `master'. (If for some reason you cannot configure
+ your system in this manner, you can probably still use the driver.
+ You may have to pass extra configuration information to the kernel
+ when you boot, however. See Documentation/ide/ide.txt for more
+ information.)
+
+4. Boot the system. If the drive is recognized, you should see a
+ message which looks like
+
+ hdb: NEC CD-ROM DRIVE:260, ATAPI CDROM drive
+
+ If you do not see this, see section 5 below.
+
+5. You may want to create a symbolic link /dev/cdrom pointing to the
+ actual device. You can do this with the command
+
+ ln -s /dev/hdX /dev/cdrom
+
+ where X should be replaced by the letter indicating where your
+ drive is installed.
+
+6. You should be able to see any error messages from the driver with
+ the `dmesg' command.
+
+
+3. Basic usage
+--------------
+
+An ISO 9660 CDROM can be mounted by putting the disc in the drive and
+typing (as root)
+
+ mount -t iso9660 /dev/cdrom /mnt/cdrom
+
+where it is assumed that /dev/cdrom is a link pointing to the actual
+device (as described in step 5 of the last section) and /mnt/cdrom is
+an empty directory. You should now be able to see the contents of the
+CDROM under the /mnt/cdrom directory. If you want to eject the CDROM,
+you must first dismount it with a command like
+
+ umount /mnt/cdrom
+
+Note that audio CDs cannot be mounted.
+
+Some distributions set up /etc/fstab to always try to mount a CDROM
+filesystem on bootup. It is not required to mount the CDROM in this
+manner, though, and it may be a nuisance if you change CDROMs often.
+You should feel free to remove the cdrom line from /etc/fstab and
+mount CDROMs manually if that suits you better.
+
+Multisession and photocd discs should work with no special handling.
+The hpcdtoppm package (ftp.gwdg.de:/pub/linux/hpcdtoppm/) may be
+useful for reading photocds.
+
+To play an audio CD, you should first unmount and remove any data
+CDROM. Any of the CDROM player programs should then work (workman,
+workbone, cdplayer, etc.).
+
+On a few drives, you can read digital audio directly using a program
+such as cdda2wav. The only types of drive which I've heard support
+this are Sony and Toshiba drives. You will get errors if you try to
+use this function on a drive which does not support it.
+
+For supported changers, you can use the `cdchange' program (appended to
+the end of this file) to switch between changer slots. Note that the
+drive should be unmounted before attempting this. The program takes
+two arguments: the CDROM device, and the slot number to which you wish
+to change. If the slot number is -1, the drive is unloaded.
+
+
+4. Common problems
+------------------
+
+This section discusses some common problems encountered when trying to
+use the driver, and some possible solutions. Note that if you are
+experiencing problems, you should probably also review
+Documentation/ide/ide.txt for current information about the underlying
+IDE support code. Some of these items apply only to earlier versions
+of the driver, but are mentioned here for completeness.
+
+In most cases, you should probably check with `dmesg' for any errors
+from the driver.
+
+a. Drive is not detected during booting.
+
+ - Review the configuration instructions above and in
+ Documentation/ide/ide.txt, and check how your hardware is
+ configured.
+
+ - If your drive is the only device on an IDE interface, it should
+ be jumpered as master, if at all possible.
+
+ - If your IDE interface is not at the standard addresses of 0x170
+ or 0x1f0, you'll need to explicitly inform the driver using a
+ lilo option. See Documentation/ide/ide.txt. (This feature was
+ added around kernel version 1.3.30.)
+
+ - If the autoprobing is not finding your drive, you can tell the
+ driver to assume that one exists by using a lilo option of the
+ form `hdX=cdrom', where X is the drive letter corresponding to
+ where your drive is installed. Note that if you do this and you
+ see a boot message like
+
+ hdX: ATAPI cdrom (?)
+
+ this does _not_ mean that the driver has successfully detected
+ the drive; rather, it means that the driver has not detected a
+ drive, but is assuming there's one there anyway because you told
+ it so. If you actually try to do I/O to a drive defined at a
+ nonexistent or nonresponding I/O address, you'll probably get
+ errors with a status value of 0xff.
+
+ - Some IDE adapters require a nonstandard initialization sequence
+ before they'll function properly. (If this is the case, there
+ will often be a separate MS-DOS driver just for the controller.)
+ IDE interfaces on sound cards often fall into this category.
+
+ Support for some interfaces needing extra initialization is
+ provided in later 1.3.x kernels. You may need to turn on
+ additional kernel configuration options to get them to work;
+ see Documentation/ide/ide.txt.
+
+ Even if support is not available for your interface, you may be
+ able to get it to work with the following procedure. First boot
+ MS-DOS and load the appropriate drivers. Then warm-boot linux
+ (i.e., without powering off). If this works, it can be automated
+ by running loadlin from the MS-DOS autoexec.
+
+
+b. Timeout/IRQ errors.
+
+ - If you always get timeout errors, interrupts from the drive are
+ probably not making it to the host.
+
+ - IRQ problems may also be indicated by the message
+ `IRQ probe failed (<n>)' while booting. If <n> is zero, that
+ means that the system did not see an interrupt from the drive when
+ it was expecting one (on any feasible IRQ). If <n> is negative,
+ that means the system saw interrupts on multiple IRQ lines, when
+ it was expecting to receive just one from the CDROM drive.
+
+ - Double-check your hardware configuration to make sure that the IRQ
+ number of your IDE interface matches what the driver expects.
+ (The usual assignments are 14 for the primary (0x1f0) interface
+ and 15 for the secondary (0x170) interface.) Also be sure that
+ you don't have some other hardware which might be conflicting with
+ the IRQ you're using. Also check the BIOS setup for your system;
+ some have the ability to disable individual IRQ levels, and I've
+ had one report of a system which was shipped with IRQ 15 disabled
+ by default.
+
+ - Note that many MS-DOS CDROM drivers will still function even if
+ there are hardware problems with the interrupt setup; they
+ apparently don't use interrupts.
+
+ - If you own a Pioneer DR-A24X, you _will_ get nasty error messages
+ on boot such as "irq timeout: status=0x50 { DriveReady SeekComplete }"
+ The Pioneer DR-A24X CDROM drives are fairly popular these days.
+ Unfortunately, these drives seem to become very confused when we perform
+ the standard Linux ATA disk drive probe. If you own one of these drives,
+ you can bypass the ATA probing which confuses these CDROM drives, by
+ adding `append="hdX=noprobe hdX=cdrom"' to your lilo.conf file and running
+ lilo (again where X is the drive letter corresponding to where your drive
+ is installed.)
+
+c. System hangups.
+
+ - If the system locks up when you try to access the CDROM, the most
+ likely cause is that you have a buggy IDE adapter which doesn't
+ properly handle simultaneous transactions on multiple interfaces.
+ The most notorious of these is the CMD640B chip. This problem can
+ be worked around by specifying the `serialize' option when
+ booting. Recent kernels should be able to detect the need for
+ this automatically in most cases, but the detection is not
+ foolproof. See Documentation/ide/ide.txt for more information
+ about the `serialize' option and the CMD640B.
+
+ - Note that many MS-DOS CDROM drivers will work with such buggy
+ hardware, apparently because they never attempt to overlap CDROM
+ operations with other disk activity.
+
+
+d. Can't mount a CDROM.
+
+ - If you get errors from mount, it may help to check `dmesg' to see
+ if there are any more specific errors from the driver or from the
+ filesystem.
+
+ - Make sure there's a CDROM loaded in the drive, and that's it's an
+ ISO 9660 disc. You can't mount an audio CD.
+
+ - With the CDROM in the drive and unmounted, try something like
+
+ cat /dev/cdrom | od | more
+
+ If you see a dump, then the drive and driver are probably working
+ OK, and the problem is at the filesystem level (i.e., the CDROM is
+ not ISO 9660 or has errors in the filesystem structure).
+
+ - If you see `not a block device' errors, check that the definitions
+ of the device special files are correct. They should be as
+ follows:
+
+ brw-rw---- 1 root disk 3, 0 Nov 11 18:48 /dev/hda
+ brw-rw---- 1 root disk 3, 64 Nov 11 18:48 /dev/hdb
+ brw-rw---- 1 root disk 22, 0 Nov 11 18:48 /dev/hdc
+ brw-rw---- 1 root disk 22, 64 Nov 11 18:48 /dev/hdd
+
+ Some early Slackware releases had these defined incorrectly. If
+ these are wrong, you can remake them by running the script
+ scripts/MAKEDEV.ide. (You may have to make it executable
+ with chmod first.)
+
+ If you have a /dev/cdrom symbolic link, check that it is pointing
+ to the correct device file.
+
+ If you hear people talking of the devices `hd1a' and `hd1b', these
+ were old names for what are now called hdc and hdd. Those names
+ should be considered obsolete.
+
+ - If mount is complaining that the iso9660 filesystem is not
+ available, but you know it is (check /proc/filesystems), you
+ probably need a newer version of mount. Early versions would not
+ always give meaningful error messages.
+
+
+e. Directory listings are unpredictably truncated, and `dmesg' shows
+ `buffer botch' error messages from the driver.
+
+ - There was a bug in the version of the driver in 1.2.x kernels
+ which could cause this. It was fixed in 1.3.0. If you can't
+ upgrade, you can probably work around the problem by specifying a
+ blocksize of 2048 when mounting. (Note that you won't be able to
+ directly execute binaries off the CDROM in that case.)
+
+ If you see this in kernels later than 1.3.0, please report it as a
+ bug.
+
+
+f. Data corruption.
+
+ - Random data corruption was occasionally observed with the Hitachi
+ CDR-7730 CDROM. If you experience data corruption, using "hdx=slow"
+ as a command line parameter may work around the problem, at the
+ expense of low system performance.
+
+
+5. cdchange.c
+-------------
+
+/*
+ * cdchange.c [-v] <device> [<slot>]
+ *
+ * This loads a CDROM from a specified slot in a changer, and displays
+ * information about the changer status. The drive should be unmounted before
+ * using this program.
+ *
+ * Changer information is displayed if either the -v flag is specified
+ * or no slot was specified.
+ *
+ * Based on code originally from Gerhard Zuber <zuber@berlin.snafu.de>.
+ * Changer status information, and rewrite for the new Uniform CDROM driver
+ * interface by Erik Andersen <andersee@debian.org>.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <linux/cdrom.h>
+
+
+int
+main (int argc, char **argv)
+{
+ char *program;
+ char *device;
+ int fd; /* file descriptor for CD-ROM device */
+ int status; /* return status for system calls */
+ int verbose = 0;
+ int slot=-1, x_slot;
+ int total_slots_available;
+
+ program = argv[0];
+
+ ++argv;
+ --argc;
+
+ if (argc < 1 || argc > 3) {
+ fprintf (stderr, "usage: %s [-v] <device> [<slot>]\n",
+ program);
+ fprintf (stderr, " Slots are numbered 1 -- n.\n");
+ exit (1);
+ }
+
+ if (strcmp (argv[0], "-v") == 0) {
+ verbose = 1;
+ ++argv;
+ --argc;
+ }
+
+ device = argv[0];
+
+ if (argc == 2)
+ slot = atoi (argv[1]) - 1;
+
+ /* open device */
+ fd = open(device, O_RDONLY | O_NONBLOCK);
+ if (fd < 0) {
+ fprintf (stderr, "%s: open failed for `%s': %s\n",
+ program, device, strerror (errno));
+ exit (1);
+ }
+
+ /* Check CD player status */
+ total_slots_available = ioctl (fd, CDROM_CHANGER_NSLOTS);
+ if (total_slots_available <= 1 ) {
+ fprintf (stderr, "%s: Device `%s' is not an ATAPI "
+ "compliant CD changer.\n", program, device);
+ exit (1);
+ }
+
+ if (slot >= 0) {
+ if (slot >= total_slots_available) {
+ fprintf (stderr, "Bad slot number. "
+ "Should be 1 -- %d.\n",
+ total_slots_available);
+ exit (1);
+ }
+
+ /* load */
+ slot=ioctl (fd, CDROM_SELECT_DISC, slot);
+ if (slot<0) {
+ fflush(stdout);
+ perror ("CDROM_SELECT_DISC ");
+ exit(1);
+ }
+ }
+
+ if (slot < 0 || verbose) {
+
+ status=ioctl (fd, CDROM_SELECT_DISC, CDSL_CURRENT);
+ if (status<0) {
+ fflush(stdout);
+ perror (" CDROM_SELECT_DISC");
+ exit(1);
+ }
+ slot=status;
+
+ printf ("Current slot: %d\n", slot+1);
+ printf ("Total slots available: %d\n",
+ total_slots_available);
+
+ printf ("Drive status: ");
+ status = ioctl (fd, CDROM_DRIVE_STATUS, CDSL_CURRENT);
+ if (status<0) {
+ perror(" CDROM_DRIVE_STATUS");
+ } else switch(status) {
+ case CDS_DISC_OK:
+ printf ("Ready.\n");
+ break;
+ case CDS_TRAY_OPEN:
+ printf ("Tray Open.\n");
+ break;
+ case CDS_DRIVE_NOT_READY:
+ printf ("Drive Not Ready.\n");
+ break;
+ default:
+ printf ("This Should not happen!\n");
+ break;
+ }
+
+ for (x_slot=0; x_slot<total_slots_available; x_slot++) {
+ printf ("Slot %2d: ", x_slot+1);
+ status = ioctl (fd, CDROM_DRIVE_STATUS, x_slot);
+ if (status<0) {
+ perror(" CDROM_DRIVE_STATUS");
+ } else switch(status) {
+ case CDS_DISC_OK:
+ printf ("Disc present.");
+ break;
+ case CDS_NO_DISC:
+ printf ("Empty slot.");
+ break;
+ case CDS_TRAY_OPEN:
+ printf ("CD-ROM tray open.\n");
+ break;
+ case CDS_DRIVE_NOT_READY:
+ printf ("CD-ROM drive not ready.\n");
+ break;
+ case CDS_NO_INFO:
+ printf ("No Information available.");
+ break;
+ default:
+ printf ("This Should not happen!\n");
+ break;
+ }
+ if (slot == x_slot) {
+ status = ioctl (fd, CDROM_DISC_STATUS);
+ if (status<0) {
+ perror(" CDROM_DISC_STATUS");
+ }
+ switch (status) {
+ case CDS_AUDIO:
+ printf ("\tAudio disc.\t");
+ break;
+ case CDS_DATA_1:
+ case CDS_DATA_2:
+ printf ("\tData disc type %d.\t", status-CDS_DATA_1+1);
+ break;
+ case CDS_XA_2_1:
+ case CDS_XA_2_2:
+ printf ("\tXA data disc type %d.\t", status-CDS_XA_2_1+1);
+ break;
+ default:
+ printf ("\tUnknown disc type 0x%x!\t", status);
+ break;
+ }
+ }
+ status = ioctl (fd, CDROM_MEDIA_CHANGED, x_slot);
+ if (status<0) {
+ perror(" CDROM_MEDIA_CHANGED");
+ }
+ switch (status) {
+ case 1:
+ printf ("Changed.\n");
+ break;
+ default:
+ printf ("\n");
+ break;
+ }
+ }
+ }
+
+ /* close device */
+ status = close (fd);
+ if (status != 0) {
+ fprintf (stderr, "%s: close failed for `%s': %s\n",
+ program, device, strerror (errno));
+ exit (1);
+ }
+
+ exit (0);
+}
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