Provided by: sg3-utils_1.36-1ubuntu1_amd64 bug

NAME

       sg_modes - reads mode pages with SCSI MODE SENSE command

SYNOPSIS

       sg_modes  [--all]  [--control=PC]  [--dbd]  [--dbout]  [--examine]  [--flexible]  [--help]
       [--hex]  [--list]  [--llbaa]  [--maxlen=LEN]  [--page=PG[,SPG]]   [--raw]   [-R]   [--six]
       [--verbose] [--version] [DEVICE]

       sg_modes  [-6]  [-a]  [-A]  [-c=PC]  [-d]  [-D]  [-e]  [-f]  [-h]  [-H] [-l] [-L] [-m=LEN]
       [-p=PG[,SPG]] [-r] [-subp=SPG] [-v] [-V] [-?] [DEVICE]

DESCRIPTION

       This utility sends a MODE SENSE SCSI command to the DEVICE and outputs the response. There
       is  a 6 byte and 10 byte (cdb) variant of the MODE SENSE command, this utility defaults to
       the 10 byte variant.

       This utility decodes mode page headers and block descriptors but outputs the  contents  of
       each  mode  page in hex. It also has no facility to change the mode page contents or block
       descriptor data. Mode page contents are decoded and can be changed by the sdparm utility.

       This utility supports two command line syntaxes, the preferred one is shown first  in  the
       synopsis  and  explained  in  this section. A later section on the old command line syntax
       outlines the second group of options.

       If no page is given (and --list is not selected) then --all is assumed. The  --all  option
       requests all mode pages (but not subpages) in a single response.

OPTIONS

       Arguments to long options are mandatory for short options as well.

       -a, --all
              output  all  the  mode  pages reported by the DEVICE. This is what the page code 63
              (0x3f) is defined to do. When used once, mode subpages are not fetched.  When  used
              twice  (e.g.  '-aa'), all mode pages and subpages are requested which is equivalent
              to '--page=63,255'.

       -c, --control=PC
              PC is the page control value. Up to four different versions of each page  are  held
              by the device:
                0 : current values (i.e. those active at present)
                1 : changeable values
                2 : default values (i.e. the manufacturer's settings)
                3 : saved values
              The  changeable  values  are bit masks showing which fields could be changed with a
              MODE SELECT. The saved values will be re-instated the next time the device is power
              cycled or reset. If this option is not given then current values [0] are assumed.

       -d, --dbd
              disable  block  descriptors. By default, block descriptors (usually one (for disks)
              or none) are returned in a MODE SENSE response. This option sets the "disable block
              descriptors"  (DBD)  bit  in  the  cdb which instructs the device not to return any
              block descriptors in its response. Older devices may not support this  setting  and
              may  return an "illegal request" sense key; alternatively they may ignore it. Oddly
              the Reduced Block Command set (RBC) requires this bit set.

       -D, --dbout
              disable outputting block descriptors. Irrespective of whether block descriptors are
              present in the response or not, they are not output.

       -e, --examine
              examine  each mode page in the range 0 through to 62 (inclusive).  If some response
              is given then print out the mode page name or number (in hex) if the  name  is  not
              known.

       -f, --flexible
              Some  devices, bridges and/or drivers attempt crude translations between MODE SENSE
              6 and 10 byte commands  without  correcting  the  response.  This  will  cause  the
              response  to  be  mis-interpreted  (usually  with  an  error saying the response is
              malformed). With this option, the length of the response  is  checked,  and  if  it
              looks  wrong,  the response is then decoded as if the other mode sense (cdb length)
              was sent.

       -h, --help
              print out the usage message then exit.

       -H, --hex
              The default action is to decode known mode page numbers (and subpage numbers)  into
              text.  When  this  option is used once, the response is output in hexadecimal. When
              this option is used twice, mode page numbers and page control values are output  in
              hex.

       -l, --list
              lists  all  common  page  and  subpage  codes and their names that are found in the
              command set that matches the peripheral type of the given DEVICE.  If no DEVICE and
              no  --page=PG  is  given then the common page and subpage codes and their names are
              listed for SBC (e.g. a disk). If no DEVICE is given and a --page=PG is  given  then
              the  common  page  and subpage codes and their names are listed for the command set
              whose peripheral device type matches the value given to PG.  For  example  'sg_mode
              --list  --page=1'  lists  the  command  mode  pages  and subpages for tape devices.
              Additionally if a sub_page_code is given then it  is  interpreted  as  a  transport
              identifier  and  command  transport  specific  mode  page codes and their names are
              listed following the main mode page list.  Other options are ignored.

       -L, --llbaa
              set the Long LBA Accepted (LLBAA) bit in the MODE SENSE (10) cdb. This bit  is  not
              defined  in  the  MODE  SENSE  (6)  cdb  so setting the '-L' and '--six' options is
              reported as an  error.  When  set  the  DEVICE  may  respond  with  16  byte  block
              descriptors  as  indicated  by  the  'LongLBA' field in the response. In most cases
              setting this option is not needed.

       -m, --maxlen=LEN
              The LEN argument is the maximum response length in bytes.  It  is  the  'allocation
              length'  field  in  the  cdb.  When  not given (or LEN is zero) then the allocation
              length field is set to 4096 for MODE SENSE (10) or 252 for MODE SENSE (6). The  LEN
              argument must be non-negative and no greater than 65535 for MODE SENSE (10) and not
              greater than 255 for MODE SENSE (6).

       -O, --old
              switch to older style options.

       -p, --page=PG
              page code to fetch. The PG is assumed to be a decimal value unless prefixed by '0x'
              or  has a trailing 'h'. It should be a value between 0 and 63 (inclusive). When not
              given and a default is required then a value of 63 (0x3f), which fetches  all  mode
              pages, is used.

       -p, --page=PG,SPG
              page  code  and  subpage  code  values  to  fetch. Both arguments are assumed to be
              decimal unless flagged as hexadecimal. The page code should be  between  0  and  63
              inclusive.  The  subpage  code  should  be between 0 and 255 inclusive. The default
              value for the subpage code is 0.

       -r, --raw
              output the response in binary to stdout. Error messages and warnings, if  any,  are
              sent  to  stderr.  When  this  option  is used twice (e.g. '-rr') then has the same
              action as '-R'

       -R     output the selected mode page to stdout a byte per line.  Each  line  contains  two
              hexadecimal   digits   (e.g.   "3e").  Useful  as  input  (after  editing)  to  the
              sg_wr_mode(8) utility.

       -6, --six
              by default this utility sends a 10 byte MODE SENSE command to the  DEVICE.  However
              some  SCSI  devices  only  support  6  byte  MODE  SENSE commands (e.g. SCSI-2 tape
              drives). This parameter forces the use of 6 byte MODE SENSE commands.

       -v, --verbose
              increase level of verbosity. Can be used multiple times.

       -V, --version
              print out version string then exit.

NOTES

       If the normal sg_modes utility fails with "illegal command operation code"  then  try  the
       '--six' (or '-6') option.

       This  utility  performs  a  SCSI  INQUIRY  command to determine the peripheral type of the
       device (e.g. 0 -> Direct Access Device (disk)) prior to sending a MODE SENSE command. This
       helps in decoding the block descriptor and mode pages.

       In  the  2.4 series of Linux kernels the DEVICE must be a SCSI generic (sg) device. In the
       2.6 series block devices (e.g. SCSI disks and DVD  drives)  can  also  be  specified.  For
       example "sg_modes -a /dev/sda" will work in the 2.6 series kernels.

EXIT STATUS

       The exit status of sg_modes is 0 when it is successful. Otherwise see the sg3_utils(8) man
       page.

OLDER COMMAND LINE OPTIONS

       The options in this section were the only ones available prior to sg3_utils version 1.23 .
       In  sg3_utils version 1.23 and later these older options can be selected by either setting
       the SG3_UTILS_OLD_OPTS environment variable or using '--old' (or '-O) as the first option.

       -6     by default this utility sends a 10 byte MODE SENSE  command  to  the  DEVICE.  This
              parameter  forces  the  use  of  6 byte MODE SENSE commands.  See --six in the main
              description.

       -a     see --all in the main description.

       -A     output all the mode pages and subpages supported by  the  DEVICE.  Same  as  '--all
              --all' in the new syntax.

       -c=PC  PC is the page control value. See --control=PC in the main description.

       -d     see --dbd in the main description.

       -D     see --dbout in the main description.

       -e     see --examine in the main description.

       -f     see --flexible in the main description.

       -h     The  default action is to decode known mode page numbers (and subpage numbers) into
              text. With this option mode page  numbers  (and  subpage  numbers)  are  output  in
              hexadecimal.

       -H     same action as the '-h' option.

       -l     see --list in the main description.

       -L     see --llbaa in the main description.

       -N     switch to the newer style options.

       -m=LEN see --maxlen=LEN in the main description.

       -p=PG  PG is page code to fetch. Should be a hexadecimal number between 0 and 3f inclusive
              (0 to 63 decimal). The default value when required is 3f (fetch all mode pages).

       -p=PG,SPG
              page code and subpage code values to fetch. The page code should be  a  hexadecimal
              number  between 0 and 3f inclusive. The subpage code should be a hexadecimal number
              between 0 and ff inclusive. The default value for the subpage code is 0.

       -r     output the selected mode page to stdout a byte per line.  Each  line  contains  two
              hexadecimal   digits   (e.g.   "3e").  Useful  as  input  (after  editing)  to  the
              sg_wr_mode(8) utility.

       -subp=SPG
              sub page code to  fetch.  Should  be  a  hexadecimal  number  between  0  and  0xff
              inclusive. The default value is 0.

       -v     increase verbosity of output.

       -V     print out version string then exit.

       -?     output usage message then exit. Ignore all other parameters.

AUTHOR

       Written by Douglas Gilbert

REPORTING BUGS

       Report bugs to <dgilbert at interlog dot com>.

COPYRIGHT

       Copyright © 2000-2012 Douglas Gilbert
       This  software  is distributed under the GPL version 2. There is NO warranty; not even for
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

       sdparm(8),  sg_wr_mode(8),  sginfo(8),  sgmode(scsirastools),   scsiinfo(net),   scu(net),
       seatools(seagate)

       All  these  utilities  offer  some  facility  to  change  mode  page (or block descriptor)
       parameters.