xref: /freebsd/share/man/man9/cd.9 (revision 4b66483fd8b6ec9417916966c646abfeac99278c)

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.\"	John-Mark Gurney.  All rights reserved.
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.\" $FreeBSD$
.\"
.Dd October 10, 1998
.Dt CD 9
.Os FreeBSD
.Sh NAME
.Nm cd
.Nd CDROM driver for the CAM SCSI subsystem
.Sh DESCRIPTION
The
.Nm
device driver provides a read only interface for CDROM drives (
.Tn SCSI
type 5)
and WORM drives (
.Tn SCSI
type 4)
that support CDROM type commands.
Some drives don't behave as the driver expects.  See the section
QUIRKS for info on possible flags.
.Sh QUIRKS
Each
.Tn CD-ROM
device can have different interpretations of the
.Tn SCSI
spec.  This can lead to drives requiring special handling in the driver.  The
following is a list of quirks that the driver recognize.  See
.Xr scsiconf 9
for more information on how to add quirk entries.
.Bl -tag -width CD_Q_BCD_TRACKS
.It Dv CD_Q_NO_TOUCH
This flag tell the driver not to probe the drive at attach time to see if
there is a disk in the drive and find out what size it is.  This flag is
currently unimplemented in the CAM
.Nm
driver.
.It Dv CD_Q_BCD_TRACKS
This flag is for broken drives that return the track numbers in packed BCD
instead of straight decimal.  If the drive seems to skip tracks
.Pq tracks 10-15 are skipped
then you have a drive that is in need of this flag.
.It Dv CD_Q_NO_CHANGER
This flag tells the driver that the device in question is not a changer.
This is only necessary for a CDROM device with multiple luns that are not a
part of a changer.
.It Dv CD_Q_CHANGER
This flag tells the driver that the given device is a multi-lun changer.
In general, the driver will figure this out automatically when it sees a
LUN greater than 0.  Setting this flag only has the effect of telling the
driver to run the initial read capacity command for LUN 0 of the changer
through the changer scheduling code.
.El
.Sh FILES
.Bl -tag -width /sys/cam/scsi/scsi_cd.c -compact
.It Pa /sys/cam/scsi/scsi_cd.c
is the driver source file.
.El
.Sh SEE ALSO
.Xr cd 4 ,
.Xr scsi 4
.Sh HISTORY
The
.Nm
manual page first appeared in
.Fx 2.2 .
.Sh AUTHORS
This
manual page was written by
.An John-Mark Gurney Aq gurney_j@efn.org .
It was updated for CAM and
.Fx 3.0
by
.An Kenneth Merry Aq ken@FreeBSD.org .