1.\" Copyright (c) 1996 2.\" Julian Elischer <julian@FreeBSD.org>. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd October 10, 1998 29.Dt CD 4 30.Os FreeBSD 31.Sh NAME 32.Nm cd 33.Nd SCSI CD-ROM driver 34.Sh SYNOPSIS 35.Cd device cd 36.Cd device cd1 at scbus0 target 4 unit 0 37.Cd options "CHANGER_MIN_BUSY_SECONDS=3" 38.Cd options "CHANGER_MAX_BUSY_SECONDS=11" 39.Sh DESCRIPTION 40The 41.Nm 42driver provides support for a 43.Tn SCSI 44.Tn CD-ROM 45(Compact Disc-Read Only Memory) drive. 46In an attempt to look like a regular disk, the 47.Nm 48driver synthesizes a partition table, with one partition covering the entire 49.Tn CD-ROM . 50It is possible to modify this partition table using 51.Xr disklabel 8 , 52but it will only last until the 53.Tn CD-ROM 54is unmounted. 55In general the interfaces are similar to those described by 56.Xr ad 4 57and 58.Xr da 4 . 59.Pp 60As the 61.Tn SCSI 62adapter is probed during boot, the 63.Tn SCSI 64bus is scanned for devices. 65Any devices found which answer as CDROM 66(type 5) or WORM (type 4) type devices will be `attached' to the 67.Nm 68driver. 69Prior to 70.Fx 2.1 , 71the first device found will be attached as 72.Li cd0 73the next, 74.Li cd1 , 75etc. 76Beginning in 77.Fx 2.1 78it is possible to specify what cd unit a device should 79come on line as; refer to 80.Xr scsi 4 81for details on kernel configuration. 82.Pp 83The system utility 84.Xr disklabel 8 85may be used to read the synthesized 86disk label 87structure, which will contain correct figures for the size of the 88.Tn CD-ROM 89should that information be required. 90.Pp 91.Sh KERNEL CONFIGURATION 92Any number of 93.Tn CD-ROM 94devices may be attached to the system regardless of system 95configuration as all resources are dynamically allocated. 96.Sh IOCTLS 97The following 98.Xr ioctl 2 99calls which apply to 100.Tn SCSI 101.Tn CD-ROM 102drives are defined 103in the header files 104.Aq Pa sys/cdio.h 105and 106.Aq Pa sys/disklabel.h . 107.Pp 108.Bl -tag -width CDIOCREADSUBCHANNEL -compact 109.It Dv DIOCGDINFO 110.It Dv DIOCSDINFO 111.Pq Li "struct disklabel" 112Read or write the in-core copy of the disklabel for the 113drive. The disklabel is initialized with information 114read from the scsi inquiry commands, and should be the same as 115the information printed at boot. This structure is defined in 116.Xr disklabel 5 . 117 118.It Dv CDIOCCAPABILITY 119.Pq Li "struct ioc_capability" 120Retrieve information from the drive on what features it supports. The 121information is returned in the following structure: 122.Bd -literal -offset indent 123struct ioc_capability { 124 u_long play_function; 125#define CDDOPLAYTRK 0x00000001 126 /* Can play tracks/index */ 127#define CDDOPLAYMSF 0x00000002 128 /* Can play msf to msf */ 129#define CDDOPLAYBLOCKS 0x00000004 130 /* Can play range of blocks */ 131#define CDDOPAUSE 0x00000100 132 /* Output can be paused */ 133#define CDDORESUME 0x00000200 134 /* Output can be resumed */ 135#define CDDORESET 0x00000400 136 /* Drive can be completely reset */ 137#define CDDOSTART 0x00000800 138 /* Audio can be started */ 139#define CDDOSTOP 0x00001000 140 /* Audio can be stopped */ 141#define CDDOPITCH 0x00002000 142 /* Audio pitch can be changed */ 143 144 u_long routing_function; 145#define CDREADVOLUME 0x00000001 146 /* Volume settings can be read */ 147#define CDSETVOLUME 0x00000002 148 /* Volume settings can be set */ 149#define CDSETMONO 0x00000100 150 /* Output can be set to mono */ 151#define CDSETSTEREO 0x00000200 152 /* Output can be set to stereo (def) */ 153#define CDSETLEFT 0x00000400 154 /* Output can be set to left only */ 155#define CDSETRIGHT 0x00000800 156 /* Output can be set to right only */ 157#define CDSETMUTE 0x00001000 158 /* Output can be muted */ 159#define CDSETPATCH 0x00008000 160 /* Direct routing control allowed */ 161 162 u_long special_function; 163#define CDDOEJECT 0x00000001 164 /* The tray can be opened */ 165#define CDDOCLOSE 0x00000002 166 /* The tray can be closed */ 167#define CDDOLOCK 0x00000004 168 /* The tray can be locked */ 169#define CDREADHEADER 0x00000100 170 /* Can read Table of Contents */ 171#define CDREADENTRIES 0x00000200 172 /* Can read TOC Entries */ 173#define CDREADSUBQ 0x00000200 174 /* Can read Subchannel info */ 175#define CDREADRW 0x00000400 176 /* Can read subcodes R-W */ 177#define CDHASDEBUG 0x00004000 178 /* The tray has dynamic debugging */ 179}; 180.Ed 181.It Dv CDIOCPLAYTRACKS 182.Pq Li "struct ioc_play_track" 183Start audio playback given a track address and length. The structure 184is defined as follows: 185.Bd -literal -offset indent 186struct ioc_play_track 187{ 188 u_char start_track; 189 u_char start_index; 190 u_char end_track; 191 u_char end_index; 192}; 193.Ed 194 195.It Dv CDIOCPLAYBLOCKS 196.Pq Li "struct ioc_play_blocks" 197Start audio playback given a block address and length. The structure 198is defined as follows: 199.Bd -literal -offset indent 200struct ioc_play_blocks 201{ 202 int blk; 203 int len; 204}; 205.Ed 206 207.It Dv CDIOCPLAYMSF 208.Pq Li "struct ioc_play_msf" 209Start audio playback given a `minutes-seconds-frames' address and 210length. The structure is defined as follows: 211.Bd -literal -offset indent 212struct ioc_play_msf 213{ 214 u_char start_m; 215 u_char start_s; 216 u_char start_f; 217 u_char end_m; 218 u_char end_s; 219 u_char end_f; 220}; 221.Ed 222 223.It Dv CDIOCREADSUBCHANNEL 224.Pq Li "struct ioc_read_subchannel" 225Read information from the subchannel at the location specified by this 226structure: 227.Bd -literal -offset indent 228struct ioc_read_subchannel { 229 u_char address_format; 230#define CD_LBA_FORMAT 1 231#define CD_MSF_FORMAT 2 232 u_char data_format; 233#define CD_SUBQ_DATA 0 234#define CD_CURRENT_POSITION 1 235#define CD_MEDIA_CATALOG 2 236#define CD_TRACK_INFO 3 237 u_char track; 238 int data_len; 239 struct cd_sub_channel_info *data; 240}; 241.Ed 242 243.It Dv CDIOREADTOCHEADER 244.Pq Li "struct ioc_toc_header" 245Return summary information about the table of contents for the mounted 246.Tn CD-ROM . 247The information is returned into the following structure: 248.Bd -literal -offset indent 249struct ioc_toc_header { 250 u_short len; 251 u_char starting_track; 252 u_char ending_track; 253}; 254.Ed 255 256.It Dv CDIOREADTOCENTRYS 257.Pq Li "struct ioc_read_toc_entry" 258Return information from the table of contents entries mentioned. (Yes, this 259command name is misspelled.) The argument structure is defined as follows: 260.Bd -literal -offset indent 261struct ioc_read_toc_entry { 262 u_char address_format; 263 u_char starting_track; 264 u_short data_len; 265 struct cd_toc_entry *data; 266}; 267.Ed 268The requested data is written into an area of size 269.Li data_len 270and pointed to by 271.Li data . 272 273.It Dv CDIOCSETPATCH 274.Pq Li "struct ioc_patch" 275Attach various audio channels to various output channels. The 276argument structure is defined thusly: 277.Bd -literal -offset indent 278struct ioc_patch { 279 u_char patch[4]; 280 /* one for each channel */ 281}; 282.Ed 283 284.It Dv CDIOCGETVOL 285.It Dv CDIOCSETVOL 286.Pq Li "struct ioc_vol" 287Get (set) information about the volume settings of the output channels. The 288argument structure is as follows: 289.Bd -literal -offset indent 290struct ioc_vol 291{ 292 u_char vol[4]; 293 /* one for each channel */ 294}; 295.Ed 296 297.It Dv CDIOCSETMONO 298Patch all output channels to all source channels. 299 300.It Dv CDIOCSETSTEREO 301Patch left source channel to the left output channel and the right 302source channel to the right output channel. 303 304.It Dv CDIOCSETMUTE 305Mute output without changing the volume settings. 306 307.It Dv CDIOCSETLEFT 308.It Dv CDIOCSETRIGHT 309Attach both output channels to the left (right) source channel. 310 311.It Dv CDIOCSETDEBUG 312.It Dv CDIOCCLRDEBUG 313Turn on (off) debugging for the appropriate device. 314 315.It Dv CDIOCPAUSE 316.It Dv CDIOCRESUME 317Pause (resume) audio play, without resetting the location of the read-head. 318 319.It Dv CDIOCRESET 320Reset the drive. 321 322.It Dv CDIOCSTART 323.It Dv CDIOCSTOP 324Tell the drive to spin-up (-down) the 325.Tn CD-ROM . 326 327.It Dv CDIOCALLOW 328.It Dv CDIOCPREVENT 329Tell the drive to allow (prevent) manual ejection of the 330.Tn CD-ROM 331disc. Not all drives support this feature. 332 333.It Dv CDIOCEJECT 334Eject the 335.Tn CD-ROM . 336 337.It Dv CDIOCCLOSE 338Tell the drive to close its door and load the media. Not all drives 339support this feature. 340 341.It Dv CDIOCPITCH 342.Pq Li "struct ioc_pitch" 343For drives that support it, this command instructs the drive to play 344the audio at a faster or slower rate than normal. Values of 345.Li speed 346between -32767 and -1 result in slower playback; a zero value 347indicates normal speed; and values from 1 to 32767 give faster 348playback. Drives with less than 16 bits of resolution will silently 349ignore less-significant bits. The structure is defined thusly: 350.Bd -literal -offset indent 351struct ioc_pitch 352{ 353 short speed; 354}; 355.Ed 356.El 357.Sh NOTES 358When a 359.Tn CD-ROM 360is changed in a drive controlled by the 361.Nm 362driver, then the act of changing the media will invalidate the 363disklabel and information held within the kernel. To stop corruption, 364all accesses to the device will be discarded until there are no more 365open file descriptors referencing the device. During this period, all 366new open attempts will be rejected. When no more open file descriptors 367reference the device, the first next open will load a new set of 368parameters (including disklabel) for the drive. 369.Pp 370The audio code in the 371.Nm 372driver only support 373.Tn SCSI-2 374standard audio commands. 375Because many 376.Tn CD-ROM 377manufacturers have not followed the standard, there are many 378.Tn CD-ROM 379drives for which audio will not work. 380Some work is planned to support 381some of the more common `broken' 382.Tn CD-ROM 383drives; however, this is not yet under way. 384.Sh CHANGER OPERATION 385This driver has built-in support for LUN-based CD changers. A LUN-based CD 386changer is a drive that can hold two or more CDs, but only has one CD 387player mechanism. Each CD in the drive shows up as a seperate logical unit 388on the 389.Tn SCSI 390bus. The 391.Nm 392driver automatically recognizes LUN-based changers, and routes commands for 393changers through an internal scheduler. The scheduler prevents changer 394"thrashing", which is caused by sending commands to different LUNs in the 395changer at the same time. 396.Pp 397The scheduler honors minimum and maximum time 398quanta that the driver will spend on a particular LUN. The minimum time 399is the guaranteed minimum amount of time that the driver will spend on a 400given LUN, even if there is no oustanding I/O for that LUN. The maximum 401time is the maximum amount of time the changer will spend on a LUN if there 402is oustdanding I/O for another LUN. If there is no outstanding I/O for 403another LUN, the driver will allow indefinite access to a given LUN. 404.Pp 405The minimum and maximum time quanta are configurable via kernel options and 406also via sysctl variables. The kernel options are: 407 408.Bl -tag -width 1234 -compact 409.It Cd options "CHANGER_MIN_BUSY_SECONDS=3" 410.It Cd options "CHANGER_MAX_BUSY_SECONDS=11" 411.El 412.Pp 413The sysctl variables are: 414.Pp 415.Bl -tag -width 1234 -compact 416.It Cd kern.cam.cd.changer.min_busy_seconds 417.It Cd kern.cam.cd.changer.max_busy_seconds 418.El 419.Pp 420It is suggested that the user try experimenting with the minimum and 421maximum timeouts via the sysctl variables to arrive at the proper values 422for your changer. Once you have settled on the proper timeouts for your 423changer, you can then put them in your kernel config file. 424.Pp 425If your system does have a LUN-based changer, you may notice that the 426probe messages for the various LUNs of the changer will continue to appear 427while the boot process is going on. This is normal, and is caused by the 428changer scheduling code. 429.Sh FILES 430.Bl -tag -width /dev/rcd[0-9][a-h] -compact 431.It Pa /dev/cd[0-9][a-h] 432block mode 433.Tn CD-ROM 434devices 435.It Pa /dev/rcd[0-9][a-h] 436raw mode 437.Tn CD-ROM 438devices 439.El 440.Sh DIAGNOSTICS 441None. 442.Sh SEE ALSO 443.Xr da 4 , 444.Xr scsi 4 , 445.Xr disklabel 5 , 446.Xr disklabel 8 , 447.Xr cd 9 448.Sh BUGS 449The names of the structures used for the third argument to 450.Fn ioctl 451were poorly chosen, and a number of spelling errors have survived in 452the names of the 453.Fn ioctl 454commands. 455.Pp 456There is no mechanism currently to set different minimum and maximum 457timeouts for different CD changers; the timeout values set by the kernel 458options or the sysctl variables apply to all LUN-based CD changers in the 459system. It is possible to implement such support, but the sysctl 460impelmentation at least would be rather inelegant, because of the current 461inability of the sysctl code to handle the addition of nodes after compile 462time. Thus, it would take one dynamically sized sysctl variable and a 463userland utility to get/set the timeout values. Implementation of separate 464timeouts for different CD devices in the kernel config file would likely 465require modification of 466.Xr config 8 467to support the two timeouts when hardwiring 468.Nm 469devices. 470.Sh HISTORY 471This 472.Nm 473driver is based upon the 474.Nm 475driver written by Julian Elischer, which appeared in 386BSD 0.1. The 476CAM version of the 477.Nm 478driver was written by Kenneth Merry and first appeared in 479.Fx 3.0 . 480