The MPX project is a Xorg extension to allow several mouse pointers and keyboards in an X session to be used at the same time. This is especially useful when using touch-sensitive screens (multitouch).
Watch the following Youtube video to see a demo:
In the Xorg version shipped with a current installation of Ubuntu, this extension is already included. This how-to will show you how to control two pointers and keyboards at the same time with the “xinput” tool.
First, call the xinput tool to list all available devices.
danilo@danilo-laptop:~$ xinput list
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ Tangtop Generic USBPS2 id=14 [slave pointer (2)]
⎜ ↳ SynPS/2 Synaptics TouchPad id=16 [slave pointer (2)]
⎜ ↳ Macintosh mouse button emulation id=17 [slave pointer (2)]
⎜ ↳ PS/2 Generic Mouse id=18 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ Power Button id=6 [slave keyboard (3)]
↳ Fujitsu FUJ02E3 id=7 [slave keyboard (3)]
↳ Video Bus id=8 [slave keyboard (3)]
↳ Fujitsu FUJ02B1 id=9 [slave keyboard (3)]
↳ Power Button id=10 [slave keyboard (3)]
↳ Sleep Button id=11 [slave keyboard (3)]
↳ Tangtop Generic USBPS2 id=13 [slave keyboard (3)]
↳ AT Translated Set 2 keyboard id=15 [slave keyboard (3)]
↳ USB Audio id=12 [slave keyboard (3)]In my case, I want to use the following four devices:
- Internal mouse: SynPS/2 Synaptics TouchPad (id=16)
- Internal keyboard: AT Translated Set 2 keyboard (id=15)
- External mouse: Tangtop Generic USBPS2 (id=14)
- External keyboard: Tangtop Generic USBPS2 (id=13)
Now, create a new master.
danilo@danilo-laptop:~$ xinput create-master secondary
You may hve noticed now that a second mouse pointer appears. This is because a new master called “secondary” has been created. Issue “xinput list” to see the new entries.
⎡ secondary pointer id=19 [master pointer (20)]
⎜ ↳ secondary XTEST pointer id=21 [slave pointer (19)]
⎣ secondary keyboard id=20 [master keyboard (19)]
↳ secondary XTEST keyboard id=22 [slave keyboard (20)]The next step is to reattach my two external input devices to the newly created master.
danilo@danilo-laptop:~$ xinput reattach 14 19 danilo@danilo-laptop:~$ xinput reattach 13 20
This will attach the pointer with the id 14 to the secondary pointer master with the id 19, and the keyboard with the id 13 to the keyboard master with the id 19.
Done! The device list now looks like this:
danilo@danilo-laptop:~$ xinput list
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ SynPS/2 Synaptics TouchPad id=16 [slave pointer (2)]
⎜ ↳ Macintosh mouse button emulation id=17 [slave pointer (2)]
⎜ ↳ PS/2 Generic Mouse id=18 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ Power Button id=6 [slave keyboard (3)]
↳ Fujitsu FUJ02E3 id=7 [slave keyboard (3)]
↳ Video Bus id=8 [slave keyboard (3)]
↳ Fujitsu FUJ02B1 id=9 [slave keyboard (3)]
↳ Power Button id=10 [slave keyboard (3)]
↳ Sleep Button id=11 [slave keyboard (3)]
↳ AT Translated Set 2 keyboard id=15 [slave keyboard (3)]
↳ USB Audio id=12 [slave keyboard (3)]
⎡ secondary pointer id=19 [master pointer (20)]
⎜ ↳ Tangtop Generic USBPS2 id=14 [slave pointer (19)]
⎜ ↳ secondary XTEST pointer id=21 [slave pointer (19)]
⎣ secondary keyboard id=20 [master keyboard (19)]
↳ Tangtop Generic USBPS2 id=13 [slave keyboard (20)]
↳ secondary XTEST keyboard id=22 [slave keyboard (20)]Now someone can work in one window using the first keyboard, and another person can work in a second window with another keyboard at the same time! Unfortunately I am not able to make a screenshot of this, as the printscreen utility seems to capture only the first pointer.
Notes: There are still a few things that are not very clear to me, e.g. with the second mouse pointer i can’t move any windows (even though i can focus them). Probably Xorg does not give the second pointer those permissions. Or maybe it has to do with the window manager. I haven’t taken a very deep look into these things yet, so I can’t tell you, but I will when I know more 
PS: In case you want to remove the newly created pointers, issue the following commands:
danilo@danilo-laptop:~$ xinput reattach 14 2 danilo@danilo-laptop:~$ xinput reattach 13 3 danilo@danilo-laptop:~$ xinput remove-master 19
Have fun.
Hinterlasse einen Kommentar