Do not work multimedia keys under GNU / Linux? Lirc will help us.

I have a multimedia keyboard , and some keys on it do not work. To make them work, there is a manual , but everything is too confused there, so I didn’t get involved with it.
Here we need to make a small digression:
In addition to the keyboard, I also have a remote control. So, I somehow stumbled upon a line in the Xorg logs:

(II) saa7134 IR (Avermedia AVerTV St: Configuring as keyboard

those. the remote is perceived as a keyboard. And at the same time, the numeric keypad on the remote control functions normally without additional software. But since the other keys on the remote are configured through lirc , the question arose: is it possible to make non-working keys on the keyboard to work through lirc? It turned out you can! Moreover, there is even an application that has the necessary features: inputlircd. Here is a quote from man (translated for "clarity"):

inputlircd is a small LIRC daemon that reads / dev / input / eventX from files (devices) and sends the received key codes to connected LIRC clients.
inputlircd does not need configuration, as uses standardized names for key codes, such as those used in the kernel. Many USB remote controls that provide HID devices, like multimedia keyboards, must work right out of the box.

In other words, this is exactly what we need :).

Note: I configured it all under Gentoo.

Install:

emerge -av inputlircd

Edit the configuration file:

vim /etc/conf.d/inputlircd

You can register several devices in INPUTLIRCD_OPT by separating them with a space. In my case, it turned out like this:

INPUTLIRCD_OPTS="/dev/input/by-path/pci-0000:02:08.0-event-ir /dev/input/event4"

In theory, it is better to specify by-path, because the number of the event (event) may change when adding / removing an input device. But for me, if you specify path for the keyboard, then the keys I needed did not work. In addition, I have two events created for the keyboard (numbered 3 and 4), and path one. And the necessary keys work only in case of event4.
Run:

/etc/init.d/inputlircd start

Add to autorun:

rc-update add inputlircd default

Now you can check the operability using irw. To do this, simply run this utility in the terminal:

irw

We try the multimedia keys and get something like this in response:

1a2 0 KEY_ZOOMIN event4
1a3 0 KEY_ZOOMOUT event4
8c 0 KEY_CALC event4

Now you need to create / edit the file ~ / .lircrc. For the key shown in the example above, the following lines can be added to this file: In this example, the keys KEY_ZOOMIN and KEY_ZOOMOUT are assigned the combinations Ctrl ++ and Ctrl + -, adopted to increase and decrease, respectively. These combinations are transmitted, as you might guess, to the current window. The KEY_CALC key is assigned to start the calculator.
begin

    prog = irxevent
    button = KEY_ZOOMIN
    config = Key ctrl-plus CurrentWindow
end
begin
    prog = irxevent
    button = KEY_ZOOMOUT
    config = Key ctrl-minus CurrentWindow
end
begin
    prog = irexec
    button = KEY_CALC
    config = kcalc
end


You can read about irexec and irxevent in man'ah or here .

Thus, you can make any multimedia keys work.