Difference between revisions of "Extra keyboard keys"
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[[Category:Keyboards]] | [[Category:Keyboards]] | ||
[[zh-CN:Extra Keyboard Keys]] | [[zh-CN:Extra Keyboard Keys]] | ||
− | {{ | + | {{Related articles start}} |
− | {{ | + | {{Related|Extra Keyboard Keys in Xorg}} |
− | {{ | + | {{Related|Extra Keyboard Keys in Console}} |
− | {{ | + | {{Related|Keyboard Configuration in Xorg}} |
− | {{ | + | {{Related|Keyboard Configuration in Console}} |
− | {{ | + | {{Related|Map scancodes to keycodes}} |
− | {{ | + | {{Related|Xmodmap}} |
− | {{ | + | {{Related articles end}} |
− | Many keyboards include some | + | Many keyboards include some ''special keys'' (also called ''hotkeys'' or ''multimedia keys''), which are supposed to execute an application or print special characters (not included in the standard national keymaps). [[udev]] contains a large database of mappings specific to individual keyboards, so common keyboards usually work out of the box. If you have very recent or uncommon piece of hardware, you may need to adjust the mapping manually. |
− | |||
− | |||
− | |||
− | + | Prerequisite for modifying the key mapping is knowing how the keys are identified on the system. There are multiple levels: | |
− | A ''' | + | * A [[Wikipedia:Scancode|scancode]] is the lowest identification number for a key, it is the value that a keyboard sends to a computer. |
+ | * A '''keycode''' is the second level of identification for a key, a ''keycode'' corresponds to a function. | ||
+ | * A '''keysym''' is the third level of identification for a key, it corresponds to a ''symbol''. It may depend on whether the Shift key or another [[Wikipedia:Modifier key|modifier key]] was also pressed. | ||
− | + | ''Scancodes'' are mapped to ''keycodes'', which are then mapped to ''keysyms'' depending on used keyboard layout. Most of your keys should already have a ''keycode'', or at least a ''scancode''. Keys without a ''scancode'' are not recognized by the kernel. | |
− | + | In Xorg, some ''keysyms'' (e.g. {{ic|XF86AudioPlay}}, {{ic|XF86AudioRaiseVolume}} etc.) can be mapped to actions (i.e. launching an external application). See [[Extra Keyboard Keys in Xorg#Map keysyms to actions]] for details. | |
− | + | In Linux console, some ''keysyms'' (e.g. {{ic|F1}} to {{ic|F246}}) can be mapped to certain actions (e.g. switch to other console or print some sequence of characters). See [[Extra Keyboard Keys in Console]] for details. | |
− | + | == Identifying key codes == | |
− | === | + | === Scancodes === |
− | + | ==== Using showkey ==== | |
− | |||
− | With the following | + | The universal way to get a ''scancode'' is to use the ''showkey'' utility. ''showkey'' waits for a key to be pressed and if none is during 10 seconds it quits, which is the only way to exit the program. To execute ''showkey'' you need to be in a [[Wikipedia:Virtual console|virtual console]], not in a graphical environment. Run the following command |
+ | |||
+ | # showkey --scancodes | ||
+ | |||
+ | and try to push keyboard keys, you should see ''scancodes'' being printed to the output. | ||
+ | |||
+ | ==== Using dmesg ==== | ||
+ | |||
+ | {{Note|This method does not provide ''scancodes'' for all keys, it only identifies the unknown keys.}} | ||
+ | |||
+ | You can get the ''scancode'' of a key by pressing the desired key and looking the output of {{ic|dmesg}} command. For example, if you get: | ||
+ | |||
+ | Unknown key pressed (translated set 2, code 0xa0 on isa0060/serio0 | ||
+ | |||
+ | then the ''scancode'' you need is {{ic|0xa0}}. | ||
+ | |||
+ | === Keycodes === | ||
+ | |||
+ | {{Warning|Note that the ''keycodes'' are different for Linux console and Xorg. Use the appropriate tool to determine the desired value.}} | ||
+ | |||
+ | ==== In console ==== | ||
+ | |||
+ | The ''keycodes'' for [[Wikipedia:Virtual console|virtual console]] are reported by the ''showkey'' utility. ''showkey'' waits for a key to be pressed and if none is during 10 seconds it quits, which is the only way to exit the program. To execute ''showkey'' you need to be in a virtual console, not in a graphical environment. Run the following command | ||
+ | |||
+ | # showkey --keycodes | ||
+ | |||
+ | and try to push keyboard keys, you should see ''keycodes'' being printed to the output. | ||
+ | |||
+ | ==== In Xorg ==== | ||
+ | |||
+ | The ''keycodes'' used by [[Xorg]] are reported by a utility called ''xev'', which is provided by the {{Pkg|xorg-xev}} package. Of course to execute ''xev'', you need to be in a graphical environment, not in the console. | ||
+ | |||
+ | With the following command you can start ''xev'' and show only the relevant parts: | ||
$ xev | grep -A2 --line-buffered '^KeyRelease' | sed -n '/keycode /s/^.*keycode \([0-9]*\).* (.*, \(.*\)).*$/\1 \2/p' | $ xev | grep -A2 --line-buffered '^KeyRelease' | sed -n '/keycode /s/^.*keycode \([0-9]*\).* (.*, \(.*\)).*$/\1 \2/p' | ||
− | + | Here is an example output: | |
+ | |||
38 a | 38 a | ||
27 r | 27 r | ||
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153 NoSymbol | 153 NoSymbol | ||
144 NoSymbol | 144 NoSymbol | ||
− | |||
− | + | In the example the keys {{ic|a}}, {{ic|r}}, {{ic|c}}, {{ic|h}} and two other multimedia keys were pressed. The former four keys with ''keycodes'' {{ic|38}}, {{ic|27}}, {{ic|54}} and {{ic|43}} are properly mapped, while the multimedia keys with ''keycodes'' {{ic|153}} and {{ic|144}} are not. The {{ic|NoSymbol}} indicates that no ''keysyms'' are assigned to those keys. | |
− | + | If you press a key and nothing appears in the terminal, it means that either the key does not have a ''scancode'', or the ''scancode'' is not mapped to a ''keycode''. | |
− | |||
− | |||
− | === 2.6 kernels === | + | ==== 2.6 kernels ==== |
+ | |||
+ | {{Out of date|Now we have 3.x kernel, is it still relevant?}} | ||
According to the keymap man page: | According to the keymap man page: | ||
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This is relevant if the keymaps obtained from showkey and the ones set by [[setkeycodes]] differ from the ones obtained by xev in X. Keep this in mind when translating the keymaps into keysyms using xmodmap (See [[Extra Keyboard Keys in Xorg]]). | This is relevant if the keymaps obtained from showkey and the ones set by [[setkeycodes]] differ from the ones obtained by xev in X. Keep this in mind when translating the keymaps into keysyms using xmodmap (See [[Extra Keyboard Keys in Xorg]]). | ||
− | + | == Mapping scancodes to keycodes == | |
− | + | See the main article: [[Map scancodes to keycodes]]. | |
− | + | == Mapping keycodes to keysyms == | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | == | ||
=== In console === | === In console === | ||
− | + | See the main article: [[Extra Keyboard Keys in Console]]. | |
− | |||
− | |||
=== In Xorg === | === In Xorg === | ||
− | + | See the main article: [[xmodmap]]. | |
== Laptops == | == Laptops == | ||
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}} | }} | ||
− | Note | + | {{Note|This may work also for other Asus notebook models.}} |
− | |||
=== Asus N56VJ (or possibly others) === | === Asus N56VJ (or possibly others) === | ||
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then check xev again. if you combine this with the acpi_osi="!Windows 2012" boot option, you may get weird results in xev, so try not using it. If this did fix things, make sure to make the module load at boot with methods described [[Kernel Modules|here]] | then check xev again. if you combine this with the acpi_osi="!Windows 2012" boot option, you may get weird results in xev, so try not using it. If this did fix things, make sure to make the module load at boot with methods described [[Kernel Modules|here]] | ||
+ | |||
+ | == See also == | ||
+ | |||
+ | * [http://keytouch.sourceforge.net/howto_keyboard/node4.html How to retrieve scancodes] by Marvin Raaijmakers | ||
+ | * [http://wiki.linuxquestions.org/wiki/Configuring_keyboards#Enabling_Keyboard_Multimedia_Keys Enabling Keyboard Multimedia Keys] - guide on LinuxQuestions wiki |
Revision as of 03:11, 1 December 2013
Many keyboards include some special keys (also called hotkeys or multimedia keys), which are supposed to execute an application or print special characters (not included in the standard national keymaps). udev contains a large database of mappings specific to individual keyboards, so common keyboards usually work out of the box. If you have very recent or uncommon piece of hardware, you may need to adjust the mapping manually.
Prerequisite for modifying the key mapping is knowing how the keys are identified on the system. There are multiple levels:
- A scancode is the lowest identification number for a key, it is the value that a keyboard sends to a computer.
- A keycode is the second level of identification for a key, a keycode corresponds to a function.
- A keysym is the third level of identification for a key, it corresponds to a symbol. It may depend on whether the Shift key or another modifier key was also pressed.
Scancodes are mapped to keycodes, which are then mapped to keysyms depending on used keyboard layout. Most of your keys should already have a keycode, or at least a scancode. Keys without a scancode are not recognized by the kernel.
In Xorg, some keysyms (e.g. XF86AudioPlay
, XF86AudioRaiseVolume
etc.) can be mapped to actions (i.e. launching an external application). See Extra Keyboard Keys in Xorg#Map keysyms to actions for details.
In Linux console, some keysyms (e.g. F1
to F246
) can be mapped to certain actions (e.g. switch to other console or print some sequence of characters). See Extra Keyboard Keys in Console for details.
Contents
Identifying key codes
Scancodes
Using showkey
The universal way to get a scancode is to use the showkey utility. showkey waits for a key to be pressed and if none is during 10 seconds it quits, which is the only way to exit the program. To execute showkey you need to be in a virtual console, not in a graphical environment. Run the following command
# showkey --scancodes
and try to push keyboard keys, you should see scancodes being printed to the output.
Using dmesg
You can get the scancode of a key by pressing the desired key and looking the output of dmesg
command. For example, if you get:
Unknown key pressed (translated set 2, code 0xa0 on isa0060/serio0
then the scancode you need is 0xa0
.
Keycodes
In console
The keycodes for virtual console are reported by the showkey utility. showkey waits for a key to be pressed and if none is during 10 seconds it quits, which is the only way to exit the program. To execute showkey you need to be in a virtual console, not in a graphical environment. Run the following command
# showkey --keycodes
and try to push keyboard keys, you should see keycodes being printed to the output.
In Xorg
The keycodes used by Xorg are reported by a utility called xev, which is provided by the xorg-xev package. Of course to execute xev, you need to be in a graphical environment, not in the console.
With the following command you can start xev and show only the relevant parts:
$ xev | grep -A2 --line-buffered '^KeyRelease' | sed -n '/keycode /s/^.*keycode \([0-9]*\).* (.*, \(.*\)).*$/\1 \2/p'
Here is an example output:
38 a 27 r 54 c 43 h 153 NoSymbol 144 NoSymbol
In the example the keys a
, r
, c
, h
and two other multimedia keys were pressed. The former four keys with keycodes 38
, 27
, 54
and 43
are properly mapped, while the multimedia keys with keycodes 153
and 144
are not. The NoSymbol
indicates that no keysyms are assigned to those keys.
If you press a key and nothing appears in the terminal, it means that either the key does not have a scancode, or the scancode is not mapped to a keycode.
2.6 kernels
According to the keymap man page:
atkbd.softraw=0
to your kernel while booting. This can be removed for later boots when the old raw functionality is not required.This is relevant if the keymaps obtained from showkey and the ones set by setkeycodes differ from the ones obtained by xev in X. Keep this in mind when translating the keymaps into keysyms using xmodmap (See Extra Keyboard Keys in Xorg).
Mapping scancodes to keycodes
See the main article: Map scancodes to keycodes.
Mapping keycodes to keysyms
In console
See the main article: Extra Keyboard Keys in Console.
In Xorg
See the main article: xmodmap.
Laptops
Asus M series
In order to have control over the light sensor and the multimedia keys on your Asus machine, you should use the following command:
# echo 0 > /sys/devices/platform/asus-laptop
To have it run on boot create a Systemd tmpfile:
/etc/tmpfiles.d/local.conf
w /sys/devices/platform/asus-laptop/ls_switch - - - - 0
Asus N56VJ (or possibly others)
if most of your special keys don't work, try loading the asus-nb-wmi kernel module with
# modprobe asus-nb-wmi
then check xev again. if you combine this with the acpi_osi="!Windows 2012" boot option, you may get weird results in xev, so try not using it. If this did fix things, make sure to make the module load at boot with methods described here
See also
- How to retrieve scancodes by Marvin Raaijmakers
- Enabling Keyboard Multimedia Keys - guide on LinuxQuestions wiki