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SETKEYCODES

Section: Maintenance Commands (8)
Updated: 24 October 2024
Index

NAME

setkeycodes - load kernel scancode-to-keycode mapping table entries

SYNOPSIS

setkeycodes[,options/]scancode keycode ...

DESCRIPTION

Thesetkeycodescommand reads its arguments two at a time, each pair of argumentsconsisting of a scancode (given in hexadecimal) and a keycode (givenin decimal). For each such pair, it tells the kernel keyboard driverto map the specified scancode to the specified keycode.

This command is useful only for people with slightly unusual keyboards,that have a few keys which produce scancodes that the kernel does notrecognize.

THEORY

The usual PC keyboard produces a series of scancodes for eachkey press and key release. (Scancodes are shown byshowkey -s, seeshowkey(1)) The kernel parses this stream of scancodes, and converts it toa stream of keycodes (key press/release events).(Keycodes are shown by showkey.)Apart from a few scancodes with special meaning, and apart fromthe sequence produced by the Pause key, and apart from shiftstaterelated scancodes, and apart from the key up/down bit,the stream of scancodes consists of unescapedscancodes xx (7 bits) and escaped scancodes e0 xx (8+7 bits).To these scancodes or scancode pairs, a corresponding keycode can beassigned (in the range 1-127).For example, if you have a Macro key that produces e0 6f accordingtoshowkey(1),the command

: setkeycodes e06f 112

will assign the keycode 112 to it, and thenloadkeys(1)can be used to define the function of this key.

USB keyboards have standardized keycodes andsetkeycodesdoesn't affect them at all.

Some older kernels might hardwire a low scancode range to theequivalent keycodes; setkeycodes will fail when you try to remapthese.

2.6 KERNELS

In 2.6 kernels key codes lie in the range 1-255, instead of 1-127.(It might be best to confine oneself to the range 1-239.)

In 2.6 kernels raw mode, or scancode mode, is not very raw at all.The code returned by showkey -s will change after use of setkeycodes.A kernel bug. See alsoshowkey(1).

OPTIONS

-C, --console=,DEV/: the console device to be used.
-V, --version: print version number.
-h, --help: print this usage message.

BUGS

The keycodes of X have nothing to do with those of Linux.Unusual keys can be made visible under Linux, but not under X.

setkeycodesaffects only the "first" input devicethat has modifiable scancode-to-keycode mapping.If there is more than one such device,setkeycodescannot change the mapping of other devices than the "first" one.

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