Provided by: ddcutil_0.9.8-2_amd64 bug

NAME

       ddcutil - Query and change monitor settings

SYNOPSIS

       ddcutil  [--adl|-a  adapter-index.display-index]  [--async]  [--bus|-b busno] [--ddc] [--display|--dis|-d
       dispno]  [--edid  256  hex  character  EDID]  [--excp]  [-f|--force]  [--force-slave-address]   [--hiddev
       hiddevdevicenumber]  [--mfg|-g  manufacturer  code] [--maxtries (comma-separated-list)] [--model|-l model
       name] [--nodetect] [--sn|-n serial number] [ --rw | --ro |  --wo]  [--show-table|--no-table]  [-s|--stats
       [stats-class]]   [-t|--terse|--brief|-v|--verbose]  [-U|--show-unsupported]  [--usb|-u  busnum.devicenum]
       [--verify | --noverify] [-V|--version] [h|--help] detect | capabilities | scs | probe | getvcp  [feature-
       code|feature-group]  |setvcp  feature-code  new-value  ] | vcpinfo [feature-code|feature-group] | dumpvcp
       [filename] | loadvcp filename ] | environment | usbenvironment'| interrogate

DESCRIPTION

       ddcutil is used to query and change monitor settings.

       ddcutil communicates with monitors implementing MCCS (Monitor  Control  Command  Set)  using  the  DDC/CI
       protocol on the I2C bus.  Normally, the video driver for the monitor exposes the I2C bus as devices named
       /dev/i2c-n.  Alternatively, ddcutil can communicate with USB  connected  monitors  implementing  the  USB
       Monitor Control Class Specification.

       The  Monitor  Control  Command  Set describes a collection of Virtual Control Panel (VCP) features that a
       monitor can implement.  Each feature is identified using a single byte.  For example, feature x10 is  the
       brightness control.

       In  general, the monitor settings that can be controlled by ddcutil are a superset of what can be changed
       using the buttons on a monitor and its on screen display.  The specific capabilities vary from monitor to
       monitor.

       A  particular  use  case  for  ddcutil  is  as  part of color profile management.  Monitor calibration is
       relative to the monitor color settings currently in effect, e.g. red gain.  ddcutil allows color  related
       settings  to  be  saved  at  the  time a monitor is calibrated, and then restored when the calibration is
       applied.

       Another common use case is to switch the monitor input source.

       This man page includes only abbreviated documentation of trace and other program diagnostic facilities.

       For extended documentation, use the "--help" option, and see http://www.ddcutil.com.

COMMANDS

       detect Report monitors

       vcpinfo [ feature-code | feature-group ]
              Describe VCP feature codes that ddcutil knows how to interpret

       capabilities
              Query the monitor's capabilities string

       getvcp [ feature-code | feature-group ]
              Report a single VCP feature value, or a group of feature values

       setvcp [+|-] feature-code new-value
              Set a single VCP feature value.  If + or - is specified, it must  be  surrounded  by  blanks,  and
              indicates a relative value change of a Continuous VCP feature.

       dumpvcp filename
              Save  color  profile  related  VCP feature values in a file.  If no file name is specified, one is
              generated and the file is saved <describe location>

       loadvcp filename
              Set VCP feature values from a file.  The monitor to which the values will be applied is determined
              by  the  monitor  identification  stored  in  the  file.   If the monitor is not attached, nothing
              happens.

       environment
              Probe the ddcutil installation environment.

       scs    Issue DDC/CI Save Current Settings request.

       usbenv Probe USB aspects of the ddcutil installation environment.

       probe  Explore the capabilities and features of a single monitor.

       interrogate
              Collect maximum information for problem diagnosis.

       chkusbmon
              Tests if hiddev device is a USB connected monitor, for use in udev rules.

COMMAND ARGUMENTS

       feature-code

       A feature-code is specified by its 2 character hex feature number, with or without a leading  "0x",  e.g.
       0x10, 10

       feature-group

       The  following  are  the  most  useful  feature  groups recognized.  For a complete list,  use the --help
       option.

       ALL|KNOWN
              All feature codes understood by ddcutil
       COLOR  Scan color related feature codes
       PROFILE
              Subset of color related feature codes that are saved and restored by dumpvcp and loadvcp
       SCAN   Scan all possible feature codes 0x00..0xff, except those known the be write-only

       Feature group names can be abbreviated to the first 3 characters.  Case is ignored.  e.g. COL, pro

       new-value

       A decimal number in the range 0..255, or hexadeciaml number in the range x00..xff.

OPTIONS

       Options for monitor selection.  If none are of these options are specified,  the  default  is  the  first
       detected monitor.  Options --mfg, --model and --sn can be specified together.
       -d,--display
              display-number logical display number (starting from 1)
       -b,--bus
              bus-number I2C bus number
       -a,--adl adapterIndex.displayIndex
              ADL adapter and display indexes
       --hiddev
              device number hiddev device number
       -u,--usb busnum.devicenum
              USB bus and device numbers
       -g,--mfg
              3 letter manufacturer code
       -l,--model
              model name
       -n,--sn
              serial number.  (This is the "serial ascii" field from the EDID, not the binary serial number.)
       -e,--edid
              256  hex  character  representation  of  the 128 byte EDID.  Needless to say, this is intended for
              program use.

       Options to control the amount and form of output.
       -t, --terse, --brief
              Show brief detail.  For command getvcp, the output is in machine readable form.
       -v, --verbose
              Show extended detail
       -U, --show-unsupported
              Normally, getvcp does not report unsupported features when querying a feature-group.  This  option
              forces output.
       --show-table | --no-table
              Normally,  getvcp does not report Table type features when querying a feature-group.  --show-table
              forces output.   --no-table is the default.
       --rw, --ro, --wo
              Limit getvcp or vcpinfo output to read-write, read-only, or (for vcpinfo) write-only features.
       --mccs  MCCS version
              Tailor vcpinfo output to a particular MCCS version, e.g. 2.1

       Options for diagnostic output.
       --stats [all|errors|tries|calls|elapsed|time]
              Report execution statistics.  If  no  argument  is  specified,  or  ALL  is  specified,  then  all
              statistics are output.  elapsed is a synonym for time.  calls implies time.
              I2C  bus communication is an inherently unreliable.  It is the responsibility of the program using
              the bus to manage retries in case of failure.   This  option  reports  retry  counts  and  various
              performance statistics.
       --ddc  Reports DDC protocol errors.  These may reflect I2C bus errors, or deviations by monitors from the
              MCCS specification.

       Options for program information.
       -h,--help
              Show program help.
       -V, --version
              Show program version.

       Options to tune execution:
       --maxtries (max-read-tries, max-write-read-tries, max-multi-part-tries)
              Adjust the number of retries
       --force-slave-address
              Take control of slave addresses on the I2C bus even they are in use.
       -f, --force
              Do not check certain parameters.
       --verify
              Verify values set by setvcp or loadvcp. (default)
       --noverify
              Do not verify values set by setvcp or loadvcp.
       --async
              If there are multiple monitors, initial  checks  are  performed  in  multiple  threads,  improving
              performance.
       --nodetect
              If  the  monitor  is  specified  by its I2C bus number (option --busno) skip the monitor detection
              phase, improving performance.

EXECUTION ENVIRONMENT

       Requires read/write access to /dev/i2c devices.  See http://www.ddcutil.com/i2c_permissions.

NVIDIA PROPRIETARY DRIVER

       Some newer Nvidia cards (e.g. GTX660Ti) require special settings to properly enable I2C support.   If you
       are using this driver and ddcctool does not work with your Nvidia card (TODO: Describe symptoms), you can
       try the following:

       Copy file /usr/local/share/ddcutil/data/90-nvidia-i2c.conf to directory /etc/X11/xorg.conf.d

       sudo cp /usr/local/share/ddcutil/data/90-nvidia-i2c.conf /etc/X11/xorg.conf.d

       This file will work "out of the box" if you do not have an /etc/X11/xorg.conf file.   If you  do,  adjust
       the Identifier value in the file to correspond to the value in the master xorg.conf file.

       (Note  that  the  above  instructions  assume  that  datadir was set to /usr/local/share when ddcutil was
       installed.  YMMV)

       For further discussion of Nvidia driver settings, see http://www.ddcutil.com/nvidia.

AMD PRORIETARY DRIVER

       AMD's proprietary video driver fglrx does not expose the I2C bus.  Instead, it provides access to the bus
       through  the AMD Display Library, aka ADL.  Owing to copyright restrictions, the ADL header files are not
       distributed with the ddcutil source.  Additional steps are required to build ddcutil with fglrx support.

       To see if your copy of ddcutil was built with fglrx support, issue the command:
       ddcutil --version

       ADL identifies monitors using an adapter-number/display-number pair.  To select  a  monitor  using  these
       numbers, specify the --adl option with a period separating the adapter-number and display-number, e.g.
       --adl 0.1

VIRTUAL MACHINES

       Virtualized  video  drivers  in  VMWare and VirtualBox do not provide I2C emulation.  Use of normal video
       drivers with PCI passthrough is possible.

EXAMPLES

       ddcutil detect
       Identify all attached monitors.

       ddcutil getvcp supported

       Show all settings that the default monitor supports and that ddcutil understands.

       ddctpp getvcp 10 --display 2
       Query the luminosity value of the second monitor.

       ddcutil setvcp 10 30 --bus 4
       Set the luminosity value for the monitor on bus /dev/i2c-4.

       ddcutil vcpinfo --verbose
       Show detailed information about VCP features that ddcutil understands.

       ddcutil interrogate > ~/ddcutil.out
       Collect maximum information about monitor capabilities and the  execution  environment,  and  direct  the
       output to a file.

DIAGNOSTICS

       Returns 0 on success, 1 on failure.

       Requesting help is regarded as success.

SEE ALSO

       The project homepage: http://www.ddcutil.com

AUTHOR

       Sanford Rockowitz (rockowitz at minsoft dot com)
       Copyright 2015-2018 Sanford Rockowitz

                                                  01 April 2018                                       ddcutil(1)