Multimedia keys on Linux

[boppreh]

Linux doesn't seem to emit any events for multimedia keys. In Windows they were already weird because of their null scan code, but in Linux literally nothing happens.

This should be fixed somehow.

[ahogen]

Linux doesn't seem to emit any events for multimedia keys.

Does this mean you can't capture a multimedia button press, or you can't send a key press?

Looking at an application where I want to send a multimedia key (not capture) so would this issue affect my use? Thanks!

[boppreh]

It's been a while, let me check...

[boppreh]

TL;DR: Yes, it works, as long as you know the scan code.

I just tried with a Fedora 25 live CD.

Pressing FN+F5 (brightness down in my laptop keyboard) results in Fedora muting the microphone. Not our fault here, but just to let you know.

keyboard correctly captured that key press with scan code of 190, even if the name was "unknown". You can check this by running python -m keyboard, which should print each key event as a small JSON object. And even better, the scan code was sufficient to reproduce the event.

This allowed me to record and replay the key presses, with the microphone correctly muting and unmuting as with a normal key press:

# python -m keyboard > events.txt
[...recording...]

# python -m keyboard < events.txt
[...replaying...]

If you are trying to emulate media keys that you don't have, I don't know what would happen. If you do try, please report back here and I'll note down for future users.

[ahogen]

Okay great. I'll go ahead and mess around with it then. Thanks for doing that little bit of research! I appreciate it!

I was looking at some of the Windows keyboard codes here, with the volume up/down/mute buttons being of particular interest.

Constant/value	Description
VK_VOLUME_MUTE 0xAD	Volume Mute key
VK_VOLUME_DONE 0xAE	Volume Down key
VK_VOLUME_UP 0xAF	Volume Up key
VK_MEDIA_NEXT_TRACK 0x80	Next track key
VK_MEDIA_PREV_TRACK 0x81	Previous Track key
VK_MEDIA_PLAY_PAUSE 0x83	Play/Pause Media key

And then there are the keyboard/keypad codes defined by the USB Implementers Forum here (pg. 56).

Usage ID (Dec)	Usage ID (Hex)	Usage Name
127	0x7F	Mute
128	0x80	Volume Up
129	0x81	Volume Down

Maybe between the two of those I get get something working.