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