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 April 9, 2014 29.Dt CD 4 30.Os 31.Sh NAME 32.Nm cd 33.Nd SCSI CD-ROM driver 34.Sh SYNOPSIS 35.Cd device cd 36.Sh DESCRIPTION 37The 38.Nm 39driver provides support for a 40.Tn SCSI 41.Tn CD-ROM 42(Compact Disc-Read Only Memory) drive. 43In an attempt to look like a regular disk, the 44.Nm 45driver synthesizes a partition table, with one partition covering the entire 46.Tn CD-ROM . 47It is possible to modify this partition table using 48.Xr disklabel 8 , 49but it will only last until the 50.Tn CD-ROM 51is unmounted. 52In general the interfaces are similar to those described by 53.Xr ada 4 54and 55.Xr da 4 . 56.Pp 57As the 58.Tn SCSI 59adapter is probed during boot, the 60.Tn SCSI 61bus is scanned for devices. 62Any devices found which answer as CDROM 63(type 5) or WORM (type 4) type devices will be `attached' to the 64.Nm 65driver. 66Prior to 67.Fx 2.1 , 68the first device found will be attached as 69.Li cd0 70the next, 71.Li cd1 , 72etc. 73Beginning in 74.Fx 2.1 75it is possible to specify what cd unit a device should 76come on line as; refer to 77.Xr scsi 4 78for details on kernel configuration. 79.Pp 80The system utility 81.Xr disklabel 8 82may be used to read the synthesized 83disk label 84structure, which will contain correct figures for the size of the 85.Tn CD-ROM 86should that information be required. 87.Sh KERNEL CONFIGURATION 88Any number of 89.Tn CD-ROM 90devices may be attached to the system regardless of system 91configuration as all resources are dynamically allocated. 92.Sh IOCTLS 93The following 94.Xr ioctl 2 95calls which apply to 96.Tn SCSI 97.Tn CD-ROM 98drives are defined 99in the header files 100.In sys/cdio.h 101and 102.In sys/disklabel.h . 103.Bl -tag -width CDIOCREADSUBCHANNEL 104.It Dv DIOCGDINFO 105.It Dv DIOCSDINFO 106.Pq Li "struct disklabel" 107Read or write the in-core copy of the disklabel for the 108drive. 109The disklabel is initialized with information 110read from the scsi inquiry commands, and should be the same as 111the information printed at boot. 112This structure is defined in the header file 113.In sys/disklabel.h . 114.It Dv CDIOCPLAYTRACKS 115.Pq Li "struct ioc_play_track" 116Start audio playback given a track address and length. 117The structure is defined as follows: 118.Bd -literal -offset indent 119struct ioc_play_track 120{ 121 u_char start_track; 122 u_char start_index; 123 u_char end_track; 124 u_char end_index; 125}; 126.Ed 127.It Dv CDIOCPLAYBLOCKS 128.Pq Li "struct ioc_play_blocks" 129Start audio playback given a block address and length. 130The structure is defined as follows: 131.Bd -literal -offset indent 132struct ioc_play_blocks 133{ 134 int blk; 135 int len; 136}; 137.Ed 138.It Dv CDIOCPLAYMSF 139.Pq Li "struct ioc_play_msf" 140Start audio playback given a `minutes-seconds-frames' address and 141length. 142The structure is defined as follows: 143.Bd -literal -offset indent 144struct ioc_play_msf 145{ 146 u_char start_m; 147 u_char start_s; 148 u_char start_f; 149 u_char end_m; 150 u_char end_s; 151 u_char end_f; 152}; 153.Ed 154.It Dv CDIOCREADSUBCHANNEL 155.Pq Li "struct ioc_read_subchannel" 156Read information from the subchannel at the location specified by this 157structure: 158.Bd -literal -offset indent 159struct ioc_read_subchannel { 160 u_char address_format; 161#define CD_LBA_FORMAT 1 162#define CD_MSF_FORMAT 2 163 u_char data_format; 164#define CD_SUBQ_DATA 0 165#define CD_CURRENT_POSITION 1 166#define CD_MEDIA_CATALOG 2 167#define CD_TRACK_INFO 3 168 u_char track; 169 int data_len; 170 struct cd_sub_channel_info *data; 171}; 172.Ed 173.It Dv CDIOREADTOCHEADER 174.Pq Li "struct ioc_toc_header" 175Return summary information about the table of contents for the mounted 176.Tn CD-ROM . 177The information is returned into the following structure: 178.Bd -literal -offset indent 179struct ioc_toc_header { 180 u_short len; 181 u_char starting_track; 182 u_char ending_track; 183}; 184.Ed 185.It Dv CDIOREADTOCENTRYS 186.Pq Li "struct ioc_read_toc_entry" 187Return information from the table of contents entries mentioned. 188.Pq Yes, this command name is misspelled. 189The argument structure is defined as follows: 190.Bd -literal -offset indent 191struct ioc_read_toc_entry { 192 u_char address_format; 193 u_char starting_track; 194 u_short data_len; 195 struct cd_toc_entry *data; 196}; 197.Ed 198The requested data is written into an area of size 199.Li data_len 200and pointed to by 201.Li data . 202.It Dv CDIOCSETPATCH 203.Pq Li "struct ioc_patch" 204Attach various audio channels to various output channels. 205The argument structure is defined thusly: 206.Bd -literal -offset indent 207struct ioc_patch { 208 u_char patch[4]; 209 /* one for each channel */ 210}; 211.Ed 212.It Dv CDIOCGETVOL 213.It Dv CDIOCSETVOL 214.Pq Li "struct ioc_vol" 215Get (set) information about the volume settings of the output channels. 216The argument structure is as follows: 217.Bd -literal -offset indent 218struct ioc_vol 219{ 220 u_char vol[4]; 221 /* one for each channel */ 222}; 223.Ed 224.It Dv CDIOCSETMONO 225Patch all output channels to all source channels. 226.It Dv CDIOCSETSTEREO 227Patch left source channel to the left output channel and the right 228source channel to the right output channel. 229.It Dv CDIOCSETMUTE 230Mute output without changing the volume settings. 231.It Dv CDIOCSETLEFT 232.It Dv CDIOCSETRIGHT 233Attach both output channels to the left (right) source channel. 234.It Dv CDIOCSETDEBUG 235.It Dv CDIOCCLRDEBUG 236Turn on (off) debugging for the appropriate device. 237.It Dv CDIOCPAUSE 238.It Dv CDIOCRESUME 239Pause (resume) audio play, without resetting the location of the read-head. 240.It Dv CDIOCRESET 241Reset the drive. 242.It Dv CDIOCSTART 243.It Dv CDIOCSTOP 244Tell the drive to spin-up (-down) the 245.Tn CD-ROM . 246.It Dv CDIOCALLOW 247.It Dv CDIOCPREVENT 248Tell the drive to allow (prevent) manual ejection of the 249.Tn CD-ROM 250disc. 251Not all drives support this feature. 252.It Dv CDIOCEJECT 253Eject the 254.Tn CD-ROM . 255.It Dv CDIOCCLOSE 256Tell the drive to close its door and load the media. 257Not all drives support this feature. 258.El 259.Sh NOTES 260When a 261.Tn CD-ROM 262is changed in a drive controlled by the 263.Nm 264driver, then the act of changing the media will invalidate the 265disklabel and information held within the kernel. 266To stop corruption, 267all accesses to the device will be discarded until there are no more 268open file descriptors referencing the device. 269During this period, all 270new open attempts will be rejected. 271When no more open file descriptors 272reference the device, the first next open will load a new set of 273parameters (including disklabel) for the drive. 274.Pp 275The audio code in the 276.Nm 277driver only support 278.Tn SCSI-2 279standard audio commands. 280As many 281.Tn CD-ROM 282manufacturers have not followed the standard, there are many 283.Tn CD-ROM 284drives for which audio will not work. 285Some work is planned to support 286some of the more common `broken' 287.Tn CD-ROM 288drives; however, this is not yet under way. 289.Sh SYSCTL VARIABLES 290The following variables are available as both 291.Xr sysctl 8 292variables and 293.Xr loader 8 294tunables: 295.Bl -tag -width 12 296.It kern.cam.cd.retry_count 297.Pp 298This variable determines how many times the 299.Nm 300driver will retry a READ or WRITE command. 301This does not affect the number of retries used during probe time or for 302the 303.Nm 304driver dump routine. 305This value currently defaults to 4. 306.It kern.cam.cd.%d.minimum_cmd_size 307.Pp 308The 309.Nm 310driver attempts to automatically determine whether the drive it is talking 311to supports 6 byte or 10 byte MODE SENSE/MODE SELECT operations. 312Many 313.Tn SCSI 314drives only support 6 byte commands, and 315.Tn ATAPI 316drives only support 10 byte commands. 317The 318.Nm 319driver first attempts to determine whether the protocol in use typically 320supports 6 byte commands by issuing a CAM Path Inquiry CCB. 321It will then default to 6 byte or 10 byte commands as appropriate. 322After that, the 323.Nm 324driver defaults to using 6 byte commands (assuming the protocol the drive 325speaks claims to support 6 byte commands), until one fails with a 326.Tn SCSI 327ILLEGAL REQUEST error. 328Then it tries the 10 byte version of the command to 329see if that works instead. 330Users can change the default via per-drive 331sysctl variables and loader tunables. 332Where 333.Dq %d 334is the unit number of the drive in question. 335Valid minimum command sizes 336are 6 and 10. 337Any value above 6 will be rounded to 10, and any value below 3386 will be rounded to 6. 339.El 340.Sh FILES 341.Bl -tag -width /dev/cd[0-9][a-h] -compact 342.It Pa /dev/cd[0-9][a-h] 343raw mode 344.Tn CD-ROM 345devices 346.El 347.Sh DIAGNOSTICS 348None. 349.Sh SEE ALSO 350.Xr cam 4 , 351.Xr da 4 , 352.Xr disklabel 8 , 353.Xr cd 9 354.Sh HISTORY 355This 356.Nm 357driver is based upon the 358.Nm 359driver written by Julian Elischer, which appeared in 360.Bx 386 0.1 . 361The 362CAM version of the 363.Nm 364driver was written by Kenneth Merry and first appeared in 365.Fx 3.0 . 366.Sh BUGS 367The names of the structures used for the third argument to 368.Fn ioctl 369were poorly chosen, and a number of spelling errors have survived in 370the names of the 371.Fn ioctl 372commands. 373