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 to stdout. When  this  option  is  used
              twice, mode page numbers and page control values are output in hex.
              When this option is used three times, the full response to the MODE SENSE command is output in hex
              to  stdout  without  any  decoding. This form can be redirected to a file (or piped) and then used
              'sdparm --inhex=' to decode.

       -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.

       This utility opens DEVICE with a read-only flag (e.g. in Unix with the O_RDONLY flag).

       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 © 2000-2015 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.

sg3_utils-1.41                                    January 2015                                       SG_MODES(8)