sbin/camcontrol/camcontrol.8

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.\" $FreeBSD: src/sbin/camcontrol/camcontrol.8,v 1.19.2.12 2003/01/08 17:55:02 njl Exp $
.\"
.Dd November 16, 2014
.Dt CAMCONTROL 8
.Os
.Sh NAME
.Nm camcontrol
.Nd CAM control program
.Sh SYNOPSIS
.Nm
.Aq Ar command
.Op device id
.Op generic args
.Op command args
.Nm
.Ic devlist
.Op Fl b
.Op Fl v
.Nm
.Ic periphlist
.Op device id
.Op Fl n Ar dev_name
.Op Fl u Ar unit_number
.Nm
.Ic tur
.Op device id
.Op generic args
.Nm
.Ic inquiry
.Op device id
.Op generic args
.Op Fl D
.Op Fl S
.Op Fl R
.Nm
.Ic reportluns
.Op device id
.Op generic args
.Op Fl c
.Op Fl l
.Op Fl r Ar reporttype
.Nm
.Ic readcap
.Op device id
.Op generic args
.Op Fl b
.Op Fl h
.Op Fl H
.Op Fl N
.Op Fl q
.Op Fl s
.Nm
.Ic start
.Op device id
.Op generic args
.Nm
.Ic stop
.Op device id
.Op generic args
.Nm
.Ic load
.Op device id
.Op generic args
.Nm
.Ic eject
.Op device id
.Op generic args
.Nm
.Ic rescan
.Aq all | bus Ns Op :target:lun
.Nm
.Ic reset
.Aq all | bus Ns Op :target:lun
.Nm
.Ic defects
.Op device id
.Op generic args
.Aq Fl f Ar format
.Op Fl P
.Op Fl G
.Nm
.Ic modepage
.Op device id
.Op generic args
.Aq Fl m Ar page
.Op Fl P Ar pgctl
.Op Fl e
.Op Fl d
.Nm
.Ic cmd
.Op device id
.Op generic args
.Aq Fl c Ar cmd Op args
.Op Fl i Ar len Ar fmt
.Bk -words
.Op Fl o Ar len Ar fmt Op args
.Ek
.Nm
.Ic debug
.Op Fl I
.Op Fl P
.Op Fl T
.Op Fl S
.Op Fl X
.Op Fl c
.Aq all|off|bus Ns Op :target Ns Op :lun
.Nm
.Ic tags
.Op device id
.Op generic args
.Op Fl N Ar tags
.Op Fl q
.Op Fl v
.Nm
.Ic negotiate
.Op device id
.Op generic args
.Op Fl c
.Op Fl D Ar enable|disable
.Op Fl O Ar offset
.Op Fl q
.Op Fl R Ar syncrate
.Op Fl T Ar enable|disable
.Op Fl U
.Op Fl W Ar bus_width
.Op Fl v
.Nm
.Ic format
.Op device id
.Op generic args
.Op Fl q
.Op Fl r
.Op Fl w
.Op Fl y
.Nm
.Ic idle
.Op device id
.Op generic args
.Op Fl t Ar time
.Nm
.Ic standby
.Op device id
.Op generic args
.Op Fl t Ar time
.Nm
.Ic sleep
.Op device id
.Op generic args
.Nm
.Ic help
.Sh DESCRIPTION
The
.Nm
utility is designed to provide a way for users to access and control the
.Dx
CAM subsystem.
.Pp
The
.Nm
utility
can cause a loss of data and/or system crashes if used improperly.  Even
expert users are encouraged to exercise caution when using this command.
Novice users should stay away from this utility.
.Pp
The
.Nm
utility has a number of primary functions, many of which support an optional
device identifier.  A device identifier can take one of three forms:
.Bl -tag -width 14n
.It deviceUNIT
Specify a device name and unit number combination, like "da5" or "cd3".
Note that character device node names (e.g. /dev/da0) are
.Em not
allowed here.
.It bus:target
Specify a bus number and target id.  The bus number can be determined from
the output of
.Dq camcontrol devlist .
The lun defaults to 0.
.It bus:target:lun
Specify the bus, target and lun for a device.  (e.g. 1:2:0)
.El
.Pp
The device identifier, if it is specified,
.Em must
come immediately after the function name, and before any generic or
function-specific arguments.  Note that the
.Fl n
and
.Fl u
arguments described below will override any device name or unit number
specified beforehand.  The
.Fl n
and
.Fl u
arguments will
.Em not
override a specified bus:target or bus:target:lun, however.
.Pp
Most of the
.Nm
primary functions support these generic arguments:
.Bl -tag -width 14n
.It Fl C Ar count
SCSI command retry count.  In order for this to work, error recovery
.Pq Fl E
must be turned on.
.It Fl E
Instruct the kernel to perform generic SCSI error recovery for the given
command.  This is needed in order for the retry count
.Pq Fl C
to be honored.  Other than retrying commands, the generic error recovery in
the code will generally attempt to spin up drives that are not spinning.
It may take some other actions, depending upon the sense code returned from
the command.
.It Fl n Ar dev_name
Specify the device type to operate on, e.g. "da", "cd".
.It Fl t Ar timeout
SCSI command timeout in seconds.  This overrides the default timeout for
any given command.
.It Fl u Ar unit_number
Specify the device unit number, e.g. "1", "5".
.It Fl v
Be verbose, print out sense information for failed SCSI commands.
.El
.Pp
Primary command functions:
.Bl -tag -width periphlist
.It Ic devlist
List all physical devices (logical units) attached to the CAM subsystem.
This also includes a list of peripheral drivers attached to each device.
With the
.Fl v
argument, SCSI bus number, adapter name and unit numbers are printed as
well.
On the other hand, with the
.Fl b
argument, only the bus adapter, and unit information will be printed, and
device information will be omitted.
.It Ic periphlist
List all peripheral drivers attached to a given physical device (logical
unit).
.It Ic tur
Send the SCSI test unit ready (0x00) command to the given device.
The
.Nm
utility will report whether the device is ready or not.
.It Ic inquiry
Send a SCSI inquiry command (0x12) to a device.  By default,
.Nm
will print out the standard inquiry data, device serial number, and
transfer rate information.  The user can specify that only certain types of
inquiry data be printed:
.Bl -tag -width 4n
.It Fl D
Get the standard inquiry data.
.It Fl S
Print out the serial number.  If this flag is the only one specified,
.Nm
will not print out "Serial Number" before the value returned by the drive.
This is to aid in script writing.
.It Fl R
Print out transfer rate information.
.El
.It Ic reportluns
Send the SCSI REPORT LUNS (0xA0) command to the given device.
By default,
.Nm
will print out the list of logical units (LUNs) supported by the target device.
There are a couple of options to modify the output:
.Bl -tag -width 01234567890123
.It Fl c
Just print out a count of LUNs, not the actual LUN numbers.
.It Fl l
Just print out the LUNs, and don't print out the count.
.It Fl r Ar reporttype
Specify the type of report to request from the target:
.Bl -tag -width 012345678
.It default
Return the default report.
This is the
.Nm
default.
Most targets will support this report if they support the REPORT LUNS
command.
.It wellknown
Return only well known LUNs.
.It all
Return all available LUNs.
.El
.El
.Pp
.Nm
will try to print out LUN numbers in a reasonable format.
It can understand the peripheral, flat, LUN and extended LUN formats.
.It Ic readcap
Send the SCSI READ CAPACITY command to the given device and display
the results.
If the device is larger than 2TB, the SCSI READ CAPACITY (16) service
action will be sent to obtain the full size of the device.
By default,
.Nm
will print out the last logical block of the device, and the blocksize of
the device in bytes.
To modify the output format, use the following options:
.Bl -tag -width 5n
.It Fl b
Just print out the blocksize, not the last block or device size.
This cannot be used with
.Fl N
or
.Fl s .
.It Fl h
Print out the device size in human readable (base 2, 1K == 1024) format.
This implies
.Fl N
and cannot be used with
.Fl q
or
.Fl b .
.It Fl H
Print out the device size in human readable (base 10, 1K == 1000) format.
.It Fl N
Print out the number of blocks in the device instead of the last logical
block.
.It Fl q
Quiet, print out the numbers only (separated by a comma if
.Fl b
or
.Fl s
are not specified).
.It Fl s
Print out the last logical block or the size of the device only, and omit
the blocksize.
.El
.It Ic start
Send the SCSI Start/Stop Unit (0x1B) command to the given device with the
start bit set.
.It Ic stop
Send the SCSI Start/Stop Unit (0x1B) command to the given device with the
start bit cleared.
.It Ic load
Send the SCSI Start/Stop Unit (0x1B) command to the given device with the
start bit set and the load/eject bit set.
.It Ic eject
Send the SCSI Start/Stop Unit (0x1B) command to the given device with the
start bit cleared and the load/eject bit set.
.It Ic rescan
Tell the kernel to scan all busses in the system (with the
.Ar all
argument), the given bus (XPT_SCAN_BUS), or bus:target:lun
(XPT_SCAN_LUN) for new devices or devices that have gone away.  The user
may specify a scan of all busses, a single bus, or a lun.  Scanning all luns
on a target isn't supported.
.It Ic reset
Tell the kernel to reset all busses in the system (with the
.Ar all
argument) or the given bus (XPT_RESET_BUS) by issuing a SCSI bus
reset for that bus, or to reset the given bus:target:lun
(XPT_RESET_DEV), typically by issuing a BUS DEVICE RESET message after
connecting to that device.
Note that this can have a destructive impact
on the system.
.It Ic defects
Send the SCSI READ DEFECT DATA (10) command (0x37) to the given device, and
print out any combination of: the total number of defects, the primary
defect list (PLIST), and the grown defect list (GLIST).
.Bl -tag -width 11n
.It Fl f Ar format
The three format options are:
.Em block ,
to print out the list as logical blocks,
.Em bfi ,
to print out the list in bytes from index format, and
.Em phys ,
to print out the list in physical sector format.  The format argument is
required.  Most drives support the physical sector format.  Some drives
support the logical block format.  Many drives, if they don't support the
requested format, return the data in an alternate format, along with sense
information indicating that the requested data format isn't supported.
The
.Nm
utility
attempts to detect this, and print out whatever format the drive returns.
If the drive uses a non-standard sense code to report that it doesn't
support the requested format,
.Nm
will probably see the error as a failure to complete the request.
.It Fl G
Print out the grown defect list.  This is a list of bad blocks that have
been remapped since the disk left the factory.
.It Fl P
Print out the primary defect list.
.El
.Pp
If neither
.Fl P
nor
.Fl G
is specified,
.Nm
will print out the number of defects given in the READ DEFECT DATA header
returned from the drive.
.It Ic modepage
Allows the user to display and optionally edit a SCSI mode page.  The mode
page formats are located in
.Pa /usr/share/misc/scsi_modes .
This can be overridden by specifying a different file in the
.Ev SCSI_MODES
environment variable.
The
.Ic modepage
command takes several arguments:
.Bl -tag -width 12n
.It Fl d
Disable block descriptors for mode sense.
.It Fl e
This flag allows the user to edit values in the mode page.
.It Fl m Ar mode_page
This specifies the number of the mode page the user would like to view
and/or edit.  This argument is mandatory.
.It Fl P Ar pgctl
This allows the user to specify the page control field.  Possible values are:
.Bl -tag -width xxx -compact
.It 0
Current values
.It 1
Changeable values
.It 2
Default values
.It 3
Saved values
.El
.El
.It Ic cmd
Allows the user to send an arbitrary SCSI CDB to any device.
The
.Ic cmd
function requires the
.Fl c
argument to specify the CDB.  Other arguments are optional, depending on
the command type.  The command and data specification syntax is documented
in
.Xr cam_cdbparse 3 .
NOTE:  If the CDB specified causes data to be transferred to or from the
SCSI device in question, you MUST specify either
.Fl i
or
.Fl o .
.Bl -tag -width 17n
.It Fl c Ar cmd Op args
This specifies the SCSI CDB.  CDBs may be 6, 10, 12 or 16 bytes.
.It Fl i Ar len Ar fmt
This specifies the amount of data to read, and how it should be displayed.
If the format is
.Sq - ,
.Ar len
bytes of data will be read from the device and written to standard output.
.It Fl o Ar len Ar fmt Op args
This specifies the amount of data to be written to a device, and the data
that is to be written.  If the format is
.Sq - ,
.Ar len
bytes of data will be read from standard input and written to the device.
.El
.It Ic debug
Turn on CAM debugging printfs in the kernel.  This requires
.Cd options CAMDEBUG
in your kernel config file.  WARNING:  enabling debugging printfs currently
causes an EXTREME number of kernel printfs.  You may have difficulty
turning off the debugging printfs once they start, since the kernel will be
busy printing messages and unable to service other requests quickly.
The
.Ic debug
function takes a number of arguments:
.Bl -tag -width 18n
.It Fl I
Enable CAM_DEBUG_INFO printfs.
.It Fl P
Enable CAM_DEBUG_PERIPH printfs.
.It Fl T
Enable CAM_DEBUG_TRACE printfs.
.It Fl S
Enable CAM_DEBUG_SUBTRACE printfs.
.It Fl X
Enable CAM_DEBUG_XPT printfs.
.It Fl c
Enable CAM_DEBUG_CDB printfs.  This will cause the kernel to print out the
SCSI CDBs sent to the specified device(s).
.It all
Enable debugging for all devices.
.It off
Turn off debugging for all devices
.It bus Ns Op :target Ns Op :lun
Turn on debugging for the given bus, target or lun.  If the lun or target
and lun are not specified, they are wildcarded.  (i.e., just specifying a
bus turns on debugging printfs for all devices on that bus.)
.El
.It Ic tags
Show or set the number of "tagged openings" or simultaneous transactions
we attempt to queue to a particular device.  By default, the
.Ic tags
command, with no command-specific arguments (i.e. only generic arguments)
prints out the "soft" maximum number of transactions that can be queued to
the device in question.  For more detailed information, use the
.Fl v
argument described below.
.Bl -tag -width 7n
.It Fl N Ar tags
Set the number of tags for the given device.  This must be between the
minimum and maximum number set in the kernel quirk table.  The default for
most devices that support tagged queueing is a minimum of 2 and a maximum
of 255.  The minimum and maximum values for a given device may be
determined by using the
.Fl v
switch.  The meaning of the
.Fl v
switch for this
.Nm
subcommand is described below.
.It Fl q
Be quiet, and don't report the number of tags.  This is generally used when
setting the number of tags.
.It Fl v
The verbose flag has special functionality for the
.Em tags
argument.  It causes
.Nm
to print out the tagged queueing related fields of the XPT_GDEV_TYPE CCB:
.Bl -tag -width 13n
.It dev_openings
This is the amount of capacity for transactions queued to a given device.
.It dev_active
This is the number of transactions currently queued to a device.
.It devq_openings
This is the kernel queue space for transactions.  This count usually mirrors
dev_openings except during error recovery operations when
the device queue is frozen (device is not allowed to receive
commands), the number of dev_openings is reduced, or transaction
replay is occurring.
.It devq_queued
This is the number of transactions waiting in the kernel queue for capacity
on the device.  This number is usually zero unless error recovery is in
progress.
.It held
The held count is the number of CCBs held by peripheral drivers that have
either just been completed or are about to be released to the transport
layer for service by a device.  Held CCBs reserve capacity on a given
device.
.It mintags
This is the current "hard" minimum number of transactions that can be
queued to a device at once.  The
.Ar dev_openings
value above cannot go below this number.  The default value for
.Ar mintags
is 2, although it may be set higher or lower for various devices.
.It maxtags
This is the "hard" maximum number of transactions that can be queued to a
device at one time.  The
.Ar dev_openings
value cannot go above this number.  The default value for
.Ar maxtags
is 255, although it may be set higher or lower for various devices.
.El
.El
.It Ic negotiate
Show or negotiate various communication parameters.  Some controllers may
not support setting or changing some of these values.  For instance, the
Adaptec 174x controllers do not support changing a device's sync rate or
offset.
The
.Nm
utility
will not attempt to set the parameter if the controller indicates that it
does not support setting the parameter.  To find out what the controller
supports, use the
.Fl v
flag.  The meaning of the
.Fl v
flag for the
.Ic negotiate
command is described below.  Also, some controller drivers don't support
setting negotiation parameters, even if the underlying controller supports
negotiation changes.  Some controllers, such as the Advansys wide
controllers, support enabling and disabling synchronous negotiation for
a device, but do not support setting the synchronous negotiation rate.
.Bl -tag -width 17n
.It Fl a
Attempt to make the negotiation settings take effect immediately by sending
a Test Unit Ready command to the device.
.It Fl c
Show or set current negotiation settings.  This is the default.
.It Fl D Ar enable|disable
Enable or disable disconnection.
.It Fl O Ar offset
Set the command delay offset.
.It Fl q
Be quiet, don't print anything.  This is generally useful when you want to
set a parameter, but don't want any status information.
.It Fl R Ar syncrate
Change the synchronization rate for a device.  The sync rate is a floating
point value specified in MHz.  So, for instance,
.Sq 20.000
is a legal value, as is
.Sq 20 .
.It Fl T Ar enable|disable
Enable or disable tagged queueing for a device.
.It Fl U
Show or set user negotiation settings.  The default is to show or set
current negotiation settings.
.It Fl v
The verbose switch has special meaning for the
.Ic negotiate
subcommand.  It causes
.Nm
to print out the contents of a Path Inquiry (XPT_PATH_INQ) CCB sent to the
controller driver.
.It Fl W Ar bus_width
Specify the bus width to negotiate with a device.  The bus width is
specified in bits.  The only useful values to specify are 8, 16, and 32
bits.  The controller must support the bus width in question in order for
the setting to take effect.
.El
.Pp
In general, sync rate and offset settings will not take effect for a
device until a command has been sent to the device.  The
.Fl a
switch above will automatically send a Test Unit Ready to the device so
negotiation parameters will take effect.
.It Ic format
Issue the
.Tn SCSI
FORMAT UNIT command to the named device.
.Pp
.Em WARNING! WARNING! WARNING!
.Pp
Low level formatting a disk will destroy ALL data on the disk.  Use
extreme caution when issuing this command.  Many users low-level format
disks that do not really need to be low-level formatted.  There are
relatively few scenarios that call for low-level formatting a disk.
One reason for
low-level formatting a disk is to initialize the disk after changing
its physical sector size.  Another reason for low-level formatting a disk
is to revive the disk if you are getting "medium format corrupted" errors
from the disk in response to read and write requests.
.Pp
Some disks take longer than others to format.  Users should specify a
timeout long enough to allow the format to complete.  The default format
timeout is 3 hours, which should be long enough for most disks.  Some hard
disks will complete a format operation in a very short period of time
(on the order of 5 minutes or less).  This is often because the drive
doesn't really support the FORMAT UNIT command -- it just accepts the
command, waits a few minutes and then returns it.
.Pp
The
.Sq format
subcommand takes several arguments that modify its default behavior.  The
.Fl q
and
.Fl y
arguments can be useful for scripts.
.Bl -tag -width 6n
.It Fl q
Be quiet, don't print any status messages.  This option will not disable
the questions, however.  To disable questions, use the
.Fl y
argument, below.
.It Fl r
Run in
.Dq report only
mode.
This will report status on a format that is already running on the drive.
.It Fl w
Issue a non-immediate format command.  By default,
.Nm
issues the FORMAT UNIT command with the immediate bit set.  This tells the
device to immediately return the format command, before the format has
actually completed.  Then,
.Nm
gathers
.Tn SCSI
sense information from the device every second to determine how far along
in the format process it is.  If the
.Fl w
argument is specified,
.Nm
will issue a non-immediate format command, and will be unable to print any
information to let the user know what percentage of the disk has been
formatted.
.It Fl y
Don't ask any questions.  By default,
.Nm
will ask the user if he/she really wants to format the disk in question,
and also if the default format command timeout is acceptable.  The user
will not be asked about the timeout if a timeout is specified on the
command line.
.El
.It Ic idle
Put ATA device into IDLE state.
Optional parameter
.Pq Fl t
specifies automatic standby timer value in seconds.
Value 0 disables timer.
.It Ic standby
Put ATA device into STANDBY state.
Optional parameter
.Pq Fl t
specifies automatic standby timer value in seconds.
Value 0 disables timer.
.It Ic sleep
Put ATA device into SLEEP state.
Note that the only way get device out of
this state may be reset.
.It Ic help
Print out verbose usage information.
.El
.Sh ENVIRONMENT
The
.Ev SCSI_MODES
variable allows the user to specify an alternate mode page format file.
.Pp
The
.Ev EDITOR
variable determines which text editor
.Nm
starts when editing mode pages.
.Sh FILES
.Bl -tag -width /usr/share/misc/scsi_modes -compact
.It Pa /usr/share/misc/scsi_modes
is the SCSI mode format database.
.It Pa /dev/xpt0
is the transport layer device.
.It Pa /dev/pass*
are the CAM application passthrough devices.
.El
.Sh EXAMPLES
.Dl camcontrol eject -n cd -u 1 -v
.Pp
Eject the CD from cd1, and print SCSI sense information if the command
fails.
.Pp
.Dl camcontrol tur da0
.Pp
Send the SCSI test unit ready command to da0.
The
.Nm
utility will report whether the disk is ready, but will not display sense
information if the command fails since the
.Fl v
switch was not specified.
.Bd -literal -offset indent
camcontrol tur da1 -E -C 4 -t 50 -v
.Ed
.Pp
Send a test unit ready command to da1.  Enable kernel error recovery.
Specify a retry count of 4, and a timeout of 50 seconds.  Enable sense
printing (with the
.Fl v
flag) if the command fails.  Since error recovery is turned on, the
disk will be spun up if it is not currently spinning.
The
.Nm
utility will report whether the disk is ready.
.Bd -literal -offset indent
camcontrol cmd -n cd -u 1 -v -c "3C 00 00 00 00 00 00 00 0e 00" \e
	-i 0xe "s1 i3 i1 i1 i1 i1 i1 i1 i1 i1 i1 i1"
.Ed
.Pp
Issue a READ BUFFER command (0x3C) to cd1.  Display the buffer size of cd1,
and display the first 10 bytes from the cache on cd1.  Display SCSI sense
information if the command fails.
.Bd -literal -offset indent
camcontrol cmd -n cd -u 1 -v -c "3B 00 00 00 00 00 00 00 0e 00" \e
	-o 14 "00 00 00 00 1 2 3 4 5 6 v v v v" 7 8 9 8
.Ed
.Pp
Issue a WRITE BUFFER (0x3B) command to cd1.  Write out 10 bytes of data,
not including the (reserved) 4 byte header.  Print out sense information if
the command fails.  Be very careful with this command, improper use may
cause data corruption.
.Bd -literal -offset indent
camcontrol modepage da3 -m 1 -e -P 3
.Ed
.Pp
Edit mode page 1 (the Read-Write Error Recover page) for da3, and save the
settings on the drive.  Mode page 1 contains a disk drive's auto read and
write reallocation settings, among other things.
.Pp
.Dl camcontrol rescan all
.Pp
Rescan all SCSI busses in the system for devices that have been added,
removed or changed.
.Pp
.Dl camcontrol rescan 0
.Pp
Rescan SCSI bus 0 for devices that have been added, removed or changed.
.Pp
.Dl camcontrol rescan 0:1:0
.Pp
Rescan SCSI bus 0, target 1, lun 0 to see if it has been added, removed, or
changed.
.Pp
.Dl camcontrol tags da5 -N 24
.Pp
Set the number of concurrent transactions for da5 to 24.
.Bd -literal -offset indent
camcontrol negotiate -n da -u 4 -T disable
.Ed
.Pp
Disable tagged queueing for da4.
.Bd -literal -offset indent
camcontrol negotiate -n da -u 3 -R 20.000 -O 15 -a
.Ed
.Pp
Negotiate a sync rate of 20MHz and an offset of 15 with da3.  Then send a
Test Unit Ready command to make the settings take effect.
.Sh SEE ALSO
.Xr cam 3 ,
.Xr cam_cdbparse 3 ,
.Xr cam 4 ,
.Xr pass 4 ,
.Xr xpt 4
.Sh HISTORY
The
.Nm
utility first appeared in
.Fx 3.0 .
.Pp
The mode page editing code and arbitrary SCSI command code are based upon
code in the old
.Xr scsi 8
utility and
.Xr scsi 3
library, written by Julian Elischer and Peter Dufault.  The
.Xr scsi 8
program first appeared in
.Bx 386 0.1.2.4 ,
and first appeared in
.Fx
in
.Fx 2.0.5 .
.Sh AUTHORS
.An Kenneth Merry Aq Mt ken@FreeBSD.org
.Sh BUGS
The code that parses the generic command line arguments doesn't know that
some of the subcommands take multiple arguments.  So if, for instance, you
tried something like this:
.Bd -literal -offset indent
camcontrol cmd -n da -u 1 -c "00 00 00 00 00 v" 0x00 -v
.Ed
.Pp
The sense information from the test unit ready command would not get
printed out, since the first
.Xr getopt 3
call in
.Nm
bails out when it sees the second argument to
.Fl c
(0x00),
above.  Fixing this behavior would take some gross code, or changes to the
.Xr getopt 3
interface.  The best way to circumvent this problem is to always make sure
to specify generic
.Nm
arguments before any command-specific arguments.