{ "content": [ { "type": "text", "text": "# sg_wr_mode(8) (man)\n\n**Summary:** sgwrmode - write (modify) SCSI mode page\n\n**Synopsis:** sgwrmode [--contents=H,H...] [--dbd] [--force] [--help] [--len=10|6] [--mask=M,M...]\n[--page=PGH[,SPGH]] [--rtd] [--save] [--six] [--verbose] [--version] DEVICE\n\n## Flags\n\n| Flag | Long | Arg | Description |\n|------|------|-----|-------------|\n| -c | --contents | — | where H,H... is a string of comma separated hex numbers each of which should resolve to a byte value (i.e. 0 to ff inclu |\n| -c | --contents | — | reads contents string from stdin. The hex numbers in the string may be comma, space, tab or linefeed (newline) separated |\n| -d | --dbd | — | disable block descriptors (DBD flag in cdb). Some device types include block descrip‐ tors in the mode data returned by |\n| -f | --force | — | force the contents string to be taken as the new mode page, or at least doesn't do checks on the existing mode page. Not |\n| -h | --help | — | output the usage message then exit. |\n| -l | --len | — | length of the SCSI commands (cdb) sent to DEVICE. The default is 10 so 10 byte MODE SENSE and MODE SELECT commands are i |\n| -m | --mask | — | where M,M... is a string of comma separated hex numbers each of which should resolve to a byte value (i.e. 0 to ff inclu |\n| -p | --page | — | where PGH is the page code value to fetch and modify. The page code is in hex and should be between 0 and 3e inclusive. |\n| -p | --page | — | where PGH is the page code value and SPGH is the subpage code value to fetch and modify. Both values are in hex. The sub |\n| -R | --rtd | — | when this option is given most other actions are bypassed and a MODE SELECT(6 or 10) command is sent to the DEVICE with |\n| -s | --save | — | changes the \"saved\" mode page when MODE SELECT is successful. By default (i.e. when --save is not used) only the \"curren |\n| -6 | --six | — | this option will cause the 6 byte variants of MODE SENSE and MODE SELECT commands to be used. The default is to use the |\n| -v | --verbose | — | increase the level of verbosity, (i.e. debug output). |\n| -V | --version | — | print the version string and then exit. |\n\n## Examples\n\n- `This utility can be used together with the sgmodes utility. To re-instate the default mode`\n- `page values (i.e. the mode page values chosen by the manufacturer of the device) as both the`\n- `current and saved mode page values the following sequence could be used:`\n- `$ sgmodes --control=2 --page=1a -r /dev/sda > t`\n- `$ sgwrmode --page=1a --contents=- --save /dev/sda < t`\n- `Next is an example of using a mask to modify the \"idle condition counter\" of the \"power con‐`\n- `dition\" mode page (0x1a) from 0x28 to 0x37. Note that the change is not saved so the \"idle`\n- `condition counter\" will revert to 0x28 after the next power cycle. The output from sgmodes`\n- `is abridged.`\n- `$ sgmodes --page=1a /dev/hdc`\n- `>> Power condition (mmc), pagecontrol: current`\n- `00 1a 0a 00 03 00 00 00 28 00 00 01 2c`\n- `$ sgwrmode -p 1a -c 0,0,0,0,0,0,0,37 -m 0,0,0,0,0,0,0,ff /dev/hdc`\n- `$ sgmodes -p 1a /dev/hdc`\n- `>> Power condition (mmc), pagecontrol: current`\n- `00 1a 0a 00 03 00 00 00 37 00 00 01 2c`\n\n## See Also\n\n- sdparm(sdparm)\n- sgmodes(sg3utils)\n- sginfo(sg3utils)\n\n## Section Outline\n\n- **NAME** (2 lines)\n- **SYNOPSIS** (3 lines)\n- **DESCRIPTION** (38 lines)\n- **OPTIONS** (2 lines) — 14 subsections\n - -c --contents (5 lines)\n - -c --contents (6 lines)\n - -d --dbd (6 lines)\n - -f --force (4 lines)\n - -h --help (2 lines)\n - -l --len (4 lines)\n - -m --mask (9 lines)\n - -p --page (4 lines)\n - -p --page (5 lines)\n - -R --rtd (5 lines)\n - -s --save (9 lines)\n - -6 --six (5 lines)\n - -v --verbose (2 lines)\n - -V --version (2 lines)\n- **NOTES** (23 lines)\n- **EXAMPLES** (22 lines)\n- **EXIT STATUS** (3 lines)\n- **AUTHORS** (2 lines)\n- **REPORTING BUGS** (2 lines)\n- **COPYRIGHT** (4 lines)\n- **SEE ALSO** (5 lines)\n\n## Full Content\n\n### NAME\n\nsgwrmode - write (modify) SCSI mode page\n\n### SYNOPSIS\n\nsgwrmode [--contents=H,H...] [--dbd] [--force] [--help] [--len=10|6] [--mask=M,M...]\n[--page=PGH[,SPGH]] [--rtd] [--save] [--six] [--verbose] [--version] DEVICE\n\n### DESCRIPTION\n\nWrites a modified mode page to DEVICE. Uses the SCSI MODE SENSE (6 or 10 byte variant) com‐\nmand to fetch the existing mode data which includes a mode page (or subpage). It then com‐\nbines that with the contents, potentially masked, and writes the modified mode page with the\nSCSI MODE SELECT (6 or 10 byte variant) command. This utility does not modify the block de‐\nscriptor(s); if any block descriptors are fetched by the MODE SENSE command then the same\nblock descriptors are written back with the following MODE SELECT command.\n\nIf the --rtd option is given then most other options apart from --save, --len=10|6 and --six\nare ignored. In this case only a MODE SELECT command is sent to the DEVICE with the RTD bit\n(Revert To Defaults) set. This bit was added to this command in SPC-5 revision 11, so older\ndevices may not support it. The Extended Inquiry VPD page has the RTDSUP bit to indicate\nwhether the DEVICE supports the RTD bit in the MODE SELECT(6 and 10) commands. When the --rtd\noption is given the rest of this section can be ignored.\n\nIf a contents argument is not given then the various components (i.e. header, block descrip‐\ntor(s) and mode page) of the \"current\" values of the existing mode page are printed out. In\nthis case the mode page is not altered on the device.\n\nIf the contents are specified, and a mask is not specified, then the contents must match the\nexisting mode page in various aspects unless the --force option is given. These include\nlength, mode page code and subpage code if applicable. If all is well then the contents\nstring is written to DEVICE as the new mode page.\n\nIf both contents and mask strings are specified then only bit positions in the contents cor‐\nresponding to set bits in the mask are taken while the existing mode page supplies bit posi‐\ntions corresponding to clear bits. When a mask is given then the mask and/or the contents\nmay be shorter than the existing mode page. If the mask is shorter than the contents then the\nremaining bytes are taken from the contents. If the contents are shorter than the existing\nmode page then the remaining bytes are taken from the existing mod page.\n\nThe force option allows the contents string to be written as the new mode page without any\nprior checks on the existing mode page. This should only be required for vendor specific mode\npages. The existing mode data is ignored apart from the block descriptors which can be sup‐\npressed with the --dbd option if need be.\n\nChanging individual fields in a mode page is probably more easily done with the sdparm util‐\nity. Fields can be identified by acronym or by a numerical descriptor.\n\n### OPTIONS\n\nArguments to long options are mandatory for short options as well.\n\n#### -c --contents\n\nwhere H,H... is a string of comma separated hex numbers each of which should resolve\nto a byte value (i.e. 0 to ff inclusive). A (single) space separated string of hex\nnumbers is also allowed but the list needs to be in quotes. This is the new contents\nof the mode page to be written to DEVICE, potentially filtered by the mask string.\n\n#### -c --contents\n\nreads contents string from stdin. The hex numbers in the string may be comma, space,\ntab or linefeed (newline) separated. If a line contains \"#\" then the remaining charac‐\nters on that line are ignored. Otherwise each non separator character should resolve\nto a byte value (i.e. 0 to ff inclusive). This forms the new contents of the mode page\nto be written to DEVICE, potentially filtered by the mask string.\n\n#### -d --dbd\n\ndisable block descriptors (DBD flag in cdb). Some device types include block descrip‐\ntors in the mode data returned by a MODE SENSE command. If so the same block descrip‐\ntors are written by the MODE SELECT command. This option instructs the MODE SENSE\ncommand not to return any block descriptors. This would be a sensible default for this\nutility apart from the fact that not all SCSI devices support the DBD bit in the cdb.\n\n#### -f --force\n\nforce the contents string to be taken as the new mode page, or at least doesn't do\nchecks on the existing mode page. Note that DEVICE may still reject the new contents\nfor the mode page. Cannot be given with the --mask=M,M... option.\n\n#### -h --help\n\noutput the usage message then exit.\n\n#### -l --len\n\nlength of the SCSI commands (cdb) sent to DEVICE. The default is 10 so 10 byte MODE\nSENSE and MODE SELECT commands are issued. Some old devices don't support the 10 byte\nvariants hence this option.\n\n#### -m --mask\n\nwhere M,M... is a string of comma separated hex numbers each of which should resolve\nto a byte value (i.e. 0 to ff inclusive). A (single) space separated string of hex\nnumbers is also allowed but the list needs to be in quotes. The mask chooses (bit by\nbit) whether the new mode page comes from the contents (mask bit set) or from the ex‐\nisting mode page (mask bit clear). If the mask string is shorter than the contents\nstring then the remaining bytes are taken from the contents string. If the contents\nstring is shorter than the existing mode page then the remaining bytes are taken from\nthe existing mode page (i.e. they are left unaltered).\n\n#### -p --page\n\nwhere PGH is the page code value to fetch and modify. The page code is in hex and\nshould be between 0 and 3e inclusive. Notice that page code 3f to fetch all mode pages\nis disallowed.\n\n#### -p --page\n\nwhere PGH is the page code value and SPGH is the subpage code value to fetch and\nmodify. Both values are in hex. The subpage code should be between 0 and fe inclusive.\nNotice that subpage code ff to fetch all mode subpages (for a given mode page or all\nmode pages in the case of 3f,ff) is disallowed.\n\n#### -R --rtd\n\nwhen this option is given most other actions are bypassed and a MODE SELECT(6 or 10)\ncommand is sent to the DEVICE with the RTD bit set. This will cause all current val‐\nues (and saved values if the --save option is also given) of all mode pages to be re‐\nverted to their default values.\n\n#### -s --save\n\nchanges the \"saved\" mode page when MODE SELECT is successful. By default (i.e. when\n--save is not used) only the \"current\" mode page values are changed when MODE SELECT\nis successful. In this case the new mode page will stay in effect until the device is\nreset (e.g. power cycled). When it restarts the \"saved\" values for the mode page\nwill be re-instated. So to make changes permanent use the --save option.\nWhen used with the --rtd option then both the current and saved values in each mode\npage are reverted to their default values. In the absence of --save option only the\ncurrent values in each mode page are reverted to their default values.\n\n#### -6 --six\n\nthis option will cause the 6 byte variants of MODE SENSE and MODE SELECT commands to\nbe used. The default is to use the 10 byte options. This option is equivalent to using\nthe --len=6 option.\n\n#### -v --verbose\n\nincrease the level of verbosity, (i.e. debug output).\n\n#### -V --version\n\nprint the version string and then exit.\n\n### NOTES\n\nThis utility does not check whether the contents string is trying to modify parts of the mode\npage which are changeable. The device should do that and if some part is not changeable then\nit should report: \"Invalid field in parameter list\".\n\nSome mode pages are not saveable. If so an attempt to use the --save option should cause an\nerror to be reported from the device: \"Illegal field in cdb\".\n\nThe device is required to do various checks before it accepts a new mode page. If these\nchecks fail then the mode page is not altered and either a \"parameter list length error\" or\nan \"invalid field in parameter list\" error is returned by the device in the sense data.\n\nThe recommended way to modify a mode page is to read it with a MODE SENSE, modify some part\nof it then write it back to the device with a MODE SELECT command. For example, reading an\nexisting mode page can be accomplished with 'sgmodes -p=1a -r /dev/sdb > mp1a.txt' (the\npower condition mode page). The mp1a.txt file can be edited and then used as the contents\nstring to this utility (e.g. 'sgwrmode -p 1a -s -c - /dev/sdb < mp1a.txt').\n\nTwo fields differ between what is read from the device with MODE SENSE and what is written to\nthe device with MODE SELECT: the mode data length is reserved (i.e. zero(es)) in a MODE SE‐\nLECT command while the PS bit ((sub)page byte 0 bit 7) in each mode (sub)page is reserved\n(zero) in a MODE SELECT command. The PS bit given in the contents string is zeroed unless\nthe --force option is selected.\n\n### EXAMPLES\n\nThis utility can be used together with the sgmodes utility. To re-instate the default mode\npage values (i.e. the mode page values chosen by the manufacturer of the device) as both the\ncurrent and saved mode page values the following sequence could be used:\n\n$ sgmodes --control=2 --page=1a -r /dev/sda > t\n$ sgwrmode --page=1a --contents=- --save /dev/sda < t\n\nNext is an example of using a mask to modify the \"idle condition counter\" of the \"power con‐\ndition\" mode page (0x1a) from 0x28 to 0x37. Note that the change is not saved so the \"idle\ncondition counter\" will revert to 0x28 after the next power cycle. The output from sgmodes\nis abridged.\n\n$ sgmodes --page=1a /dev/hdc\n>> Power condition (mmc), pagecontrol: current\n00 1a 0a 00 03 00 00 00 28 00 00 01 2c\n\n$ sgwrmode -p 1a -c 0,0,0,0,0,0,0,37 -m 0,0,0,0,0,0,0,ff /dev/hdc\n\n$ sgmodes -p 1a /dev/hdc\n>> Power condition (mmc), pagecontrol: current\n00 1a 0a 00 03 00 00 00 37 00 00 01 2c\n\n### EXIT STATUS\n\nThe exit status of sgwrmode is 0 when it is successful. Otherwise see the sg3utils(8) man\npage.\n\n### AUTHORS\n\nWritten by Douglas Gilbert.\n\n### REPORTING BUGS\n\nReport bugs to .\n\n### COPYRIGHT\n\nCopyright © 2004-2018 Douglas Gilbert\nThis software is distributed under a FreeBSD license. There is NO warranty; not even for MER‐\nCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\n### SEE ALSO\n\nsdparm(sdparm), sgmodes(sg3utils), sginfo(sg3utils)\n\n\n\nsg3utils-1.43 April 2018 SGWRMODE(8)\n\n" } ], "structuredContent": { "command": "sg_wr_mode", "section": "8", "mode": "man", "summary": "sgwrmode - write (modify) SCSI mode page", "synopsis": "sgwrmode [--contents=H,H...] [--dbd] [--force] [--help] [--len=10|6] [--mask=M,M...]\n[--page=PGH[,SPGH]] [--rtd] [--save] [--six] [--verbose] [--version] DEVICE", "tldr_summary": null, "tldr_examples": [], "tldr_source": null, "flags": [ { "flag": "-c", "long": "--contents", "arg": null, "description": "where H,H... is a string of comma separated hex numbers each of which should resolve to a byte value (i.e. 0 to ff inclusive). A (single) space separated string of hex numbers is also allowed but the list needs to be in quotes. This is the new contents of the mode page to be written to DEVICE, potentially filtered by the mask string." }, { "flag": "-c", "long": "--contents", "arg": null, "description": "reads contents string from stdin. The hex numbers in the string may be comma, space, tab or linefeed (newline) separated. If a line contains \"#\" then the remaining charac‐ ters on that line are ignored. Otherwise each non separator character should resolve to a byte value (i.e. 0 to ff inclusive). This forms the new contents of the mode page to be written to DEVICE, potentially filtered by the mask string." }, { "flag": "-d", "long": "--dbd", "arg": null, "description": "disable block descriptors (DBD flag in cdb). Some device types include block descrip‐ tors in the mode data returned by a MODE SENSE command. If so the same block descrip‐ tors are written by the MODE SELECT command. This option instructs the MODE SENSE command not to return any block descriptors. This would be a sensible default for this utility apart from the fact that not all SCSI devices support the DBD bit in the cdb." }, { "flag": "-f", "long": "--force", "arg": null, "description": "force the contents string to be taken as the new mode page, or at least doesn't do checks on the existing mode page. Note that DEVICE may still reject the new contents for the mode page. Cannot be given with the --mask=M,M... option." }, { "flag": "-h", "long": "--help", "arg": null, "description": "output the usage message then exit." }, { "flag": "-l", "long": "--len", "arg": null, "description": "length of the SCSI commands (cdb) sent to DEVICE. The default is 10 so 10 byte MODE SENSE and MODE SELECT commands are issued. Some old devices don't support the 10 byte variants hence this option." }, { "flag": "-m", "long": "--mask", "arg": null, "description": "where M,M... is a string of comma separated hex numbers each of which should resolve to a byte value (i.e. 0 to ff inclusive). A (single) space separated string of hex numbers is also allowed but the list needs to be in quotes. The mask chooses (bit by bit) whether the new mode page comes from the contents (mask bit set) or from the ex‐ isting mode page (mask bit clear). If the mask string is shorter than the contents string then the remaining bytes are taken from the contents string. If the contents string is shorter than the existing mode page then the remaining bytes are taken from the existing mode page (i.e. they are left unaltered)." }, { "flag": "-p", "long": "--page", "arg": null, "description": "where PGH is the page code value to fetch and modify. The page code is in hex and should be between 0 and 3e inclusive. Notice that page code 3f to fetch all mode pages is disallowed." }, { "flag": "-p", "long": "--page", "arg": null, "description": "where PGH is the page code value and SPGH is the subpage code value to fetch and modify. Both values are in hex. The subpage code should be between 0 and fe inclusive. Notice that subpage code ff to fetch all mode subpages (for a given mode page or all mode pages in the case of 3f,ff) is disallowed." }, { "flag": "-R", "long": "--rtd", "arg": null, "description": "when this option is given most other actions are bypassed and a MODE SELECT(6 or 10) command is sent to the DEVICE with the RTD bit set. This will cause all current val‐ ues (and saved values if the --save option is also given) of all mode pages to be re‐ verted to their default values." }, { "flag": "-s", "long": "--save", "arg": null, "description": "changes the \"saved\" mode page when MODE SELECT is successful. By default (i.e. when --save is not used) only the \"current\" mode page values are changed when MODE SELECT is successful. In this case the new mode page will stay in effect until the device is reset (e.g. power cycled). When it restarts the \"saved\" values for the mode page will be re-instated. So to make changes permanent use the --save option. When used with the --rtd option then both the current and saved values in each mode page are reverted to their default values. In the absence of --save option only the current values in each mode page are reverted to their default values." }, { "flag": "-6", "long": "--six", "arg": null, "description": "this option will cause the 6 byte variants of MODE SENSE and MODE SELECT commands to be used. The default is to use the 10 byte options. This option is equivalent to using the --len=6 option." }, { "flag": "-v", "long": "--verbose", "arg": null, "description": "increase the level of verbosity, (i.e. debug output)." }, { "flag": "-V", "long": "--version", "arg": null, "description": "print the version string and then exit." } ], "examples": [ "This utility can be used together with the sgmodes utility. To re-instate the default mode", "page values (i.e. the mode page values chosen by the manufacturer of the device) as both the", "current and saved mode page values the following sequence could be used:", "$ sgmodes --control=2 --page=1a -r /dev/sda > t", "$ sgwrmode --page=1a --contents=- --save /dev/sda < t", "Next is an example of using a mask to modify the \"idle condition counter\" of the \"power con‐", "dition\" mode page (0x1a) from 0x28 to 0x37. Note that the change is not saved so the \"idle", "condition counter\" will revert to 0x28 after the next power cycle. The output from sgmodes", "is abridged.", "$ sgmodes --page=1a /dev/hdc", ">> Power condition (mmc), pagecontrol: current", "00 1a 0a 00 03 00 00 00 28 00 00 01 2c", "$ sgwrmode -p 1a -c 0,0,0,0,0,0,0,37 -m 0,0,0,0,0,0,0,ff /dev/hdc", "$ sgmodes -p 1a /dev/hdc", ">> Power condition (mmc), pagecontrol: current", "00 1a 0a 00 03 00 00 00 37 00 00 01 2c" ], "see_also": [ { "name": "sdparm", "section": "sdparm", "url": "https://www.chedong.com/phpMan.php/man/sdparm/sdparm/json" }, { "name": "sgmodes", "section": "sg3utils", "url": "https://www.chedong.com/phpMan.php/man/sgmodes/sg3utils/json" }, { "name": "sginfo", "section": "sg3utils", "url": "https://www.chedong.com/phpMan.php/man/sginfo/sg3utils/json" } ], "section_outline": [ { "name": "NAME", "lines": 2, "subsections": [] }, { "name": "SYNOPSIS", "lines": 3, "subsections": [] }, { "name": "DESCRIPTION", "lines": 38, "subsections": [] }, { "name": "OPTIONS", "lines": 2, "subsections": [ { "name": "-c --contents", "lines": 5, "flag": "-c", "long": "--contents" }, { "name": "-c --contents", "lines": 6, "flag": "-c", "long": "--contents" }, { "name": "-d --dbd", "lines": 6, "flag": "-d", "long": "--dbd" }, { "name": "-f --force", "lines": 4, "flag": "-f", "long": "--force" }, { "name": "-h --help", "lines": 2, "flag": "-h", "long": "--help" }, { "name": "-l --len", "lines": 4, "flag": "-l", "long": "--len" }, { "name": "-m --mask", "lines": 9, "flag": "-m", "long": "--mask" }, { "name": "-p --page", "lines": 4, "flag": "-p", "long": "--page" }, { "name": "-p --page", "lines": 5, "flag": "-p", "long": "--page" }, { "name": "-R --rtd", "lines": 5, "flag": "-R", "long": "--rtd" }, { "name": "-s --save", "lines": 9, "flag": "-s", "long": "--save" }, { "name": "-6 --six", "lines": 5, "flag": "-6", "long": "--six" }, { "name": "-v --verbose", "lines": 2, "flag": "-v", "long": "--verbose" }, { "name": "-V --version", "lines": 2, "flag": "-V", "long": "--version" } ] }, { "name": "NOTES", "lines": 23, "subsections": [] }, { "name": "EXAMPLES", "lines": 22, "subsections": [] }, { "name": "EXIT STATUS", "lines": 3, "subsections": [] }, { "name": "AUTHORS", "lines": 2, "subsections": [] }, { "name": "REPORTING BUGS", "lines": 2, "subsections": [] }, { "name": "COPYRIGHT", "lines": 4, "subsections": [] }, { "name": "SEE ALSO", "lines": 5, "subsections": [] } ] } }