— CDROM driver for the CAM SCSI
device driver provides a read only interface for CDROM
drives (SCSI type 5) and WORM drives (SCSI type 4) that support CDROM type
commands. Some drives do not behave as the driver expects. See the
section for information on possible
Each CD-ROM device can have different interpretations of the SCSI spec. This can
lead to drives requiring special handling in the driver. The following is a
list of quirks that the driver recognize.
- 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 cd
- 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 (tracks 10-15 are skipped) then you have a drive that is in
need of this flag.
- 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.
- 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.
- This flag tells the driver that the given device only
accepts 10 byte MODE SENSE/MODE SELECT commands. In general these types of
quirks should not be added to the cd(4) driver. The
reason is that the driver does several things to attempt to determine
whether the drive in question needs 10 byte commands. First, it issues a
CAM Path Inquiry command to determine whether the protocol that the drive
speaks typically only allows 10 byte commands. (ATAPI and USB are two
prominent examples of protocols where you generally only want to send 10
byte commands.) Then, if it gets an ILLEGAL REQUEST error back from a 6
byte MODE SENSE or MODE SELECT command, it attempts to send the 10 byte
version of the command instead. The only reason you would need a quirk is
if your drive uses a protocol (e.g., SCSI) that typically does not have a
problem with 6 byte commands.
- is the driver source file.
manual page first appeared in FreeBSD
This manual page was written by John-Mark Gurney
⟨email@example.com⟩. It was updated for CAM and
by Kenneth Merry