Command getvcp

Syntax: getvcp <display-selection-options> <other options> <feature-codes-or-group>

Monitor selection options are detailed here.

Feature code/group specification is detailed here. Briefly, you can specify one or more feature codes or a feature group, but feature codes and groups cannot be combined. For example, the folling commands are valid:

$ ddcutil getvcp 10 12

$ ddcutil getvcp color

(Note: The ability to specify multiple feature codes was added in release 1.3.0)

If a feature group has been specified, there is normally no message if a feature is unsupported. This rule is not absolute. For some feature-groups it is appropriate to always report that a feature is unsupported. This is also affected by the --show-unsupported option described below.

Option: --terse, --brief

If --terse is specified on a getvcp command, output is in a format this is easily machine readable. This format is also used by dumpvcp.

The format depends on the feature type. In keeping with ddcutil practice, VCP feature codes are shown without a leading hex indicator even though they are hexidecimal values.

For a continuous VCP feature, both the current value (in decimal) and maximum value (in decimal) are shown. Output takes the form:

  VCP feature-code C cur-value-decimal max-value-decimal

For example:

VCP 10 C 50 100

For a simple non-continuous VCP feature, i.e. one for which only the SL response byte is significant, the value is reported in hex. Output takes the form:

  VCP feature-code SNC hex-value

For example:

VCP 60 SNC x03

Complex non-continuous VCP features are ones for which more then 1 response byte is significant. In that case all 4 bytes are reported in hex. Output takes the form:

  VCP feature-code CNC mh-hex ml-hex sh-hex sl-hex

For example:

VCP DF CND xff xff x02 x00

Table VCP features report the value as hexidecimal string. Output takes the form:

  VCP feature-code T hex-string

For example:

VCP 73 T x01020304

Finally, if a feature is not supported or some other error occurs, this may be reported or there may simply be no output. It is always reported for single feature getvcp requests. It is normally not reported if the request specifies a feature group, which defines a set of features. but see --show-unsupported. If reported, output takes the form:

  VCP feature-code ERR

For example:

VCP 84 ERR

Option: --verbose

The internal representation (bytes MH, ML, SH, SL) is shown. Unsupported features are always reported.

Option: --show-unsupported

If querying a single feature, getvcp reports an error if the feature is unsupported or some other error occurs. If querying a feature group, e.g. COLOR, output for invalid features is suppressd unless --verbose is specified. The --show-unsupported option forces error messages in all cases.

Option: --mccs <vcp-version>

Interprets the feature value as per the specified VCP (aka MCCS) version, instead of using the VCP version obtained from VCP feature xDF.