--- /dev/null
+title: X Keyboard Specific Mappings
+linktitle: xkbmap
+parent: 2015-01
+ctime: 2015-01-30
+mtime: 2015-01-30
+
+# Why global keyboard remapping can be bad
+
+In an [[earlier post|swapkeys]], I blogged about remapping keys on a keyboard
+for better typing comfort. The change was to swap the Control and Windows keys
+on a [CM Storm Stealth](http://gaming.coolermaster.com/en/products/keyboards/stealth/)
+USB keyboard.
+
+![CM Storm Stealth keyboard][cmstorm_img]
+
+Using the "partial fist" method I described in my [[prior post|swapkeys]], the
+pinky ends up hitting the Windows key, both with left and right pinkies. And
+because I use vim heavily, I want the control key at this position. The CM
+Storm keyboard is nice because its placement of the Control and Window keys are
+symmetrical in relation to the hands on the home row of the keyboard.
+
+The xmodmap mappings described in my [[earlier post|swapkeys]] works fine to
+swap the Control and Windows keys, but because it changes the mappings globally,
+it remaps the Control and Windows keys on all attached keyboards. I use a
+Thinkpad X201 notebook, and swapping its Control and Windows keys is not
+desirable.
+
+![Thinkpad X201 keyboard][x201_keyboard_img]
+
+The position of the Control keys on the Thinkpad keyboard is already ideal
+according to my preference. So what I really want is a method to change the
+mappings for only one keyboard device attached to the computer, and not all of
+them.
+
+# How to implement device specific remapping
+
+[[!pquote text="xkb allows per-device mapping"]]
+
+The solution is to ditch the xmodmap solution presented [[before|swapkeys]] and
+instead use the capabilities of xkb. Using the Xorg evdev input driver, it is
+possible to configure different settings for different input devices. For
+keyboards, we can therefore select different xkb options.
+
+The configuration changes describe here are available in the
+[cmstorm](/gitweb/?p=cmstorm.git;a=summary) repository.
+
+## Step 1 -- Create a new xkb option
+
+I first created a new xkb option. New file `/usr/share/X11/xkb/symbols/ctrlwin`
+contains the option named `ctrlwin:swap_ctrl_win`:
+
+
+ // Swap the Ctrl and Win keys.
+ partial modifier_keys
+ xkb_symbols "swap_ctrl_win" {
+ key <LWIN> { [ Control_L ] };
+ key <LCTL> { [ Super_L ] };
+ key <RWIN> { [ Control_R ] };
+ key <RCTL> { [ Super_R ] };
+ };
+
+## Step 2 -- Reference the new option so it can be used
+
+The new option should show up in the proper reference files to be usable.
+Specifically, the evdev and evdev.lst files, found in the
+`/usr/share/X11/xkb/rules` directory, at least on Ubuntu 14.04.
+
+Here's the patch for evdev.
+
+ --- evdev.orig 2014-01-15 07:42:33.000000000 -0700
+ +++ evdev 2015-01-30 20:20:08.708389769 -0700
+ @@ -971,6 +971,7 @@
+ altwin:hyper_win = +altwin(hyper_win)
+ altwin:alt_super_win = +altwin(alt_super_win)
+ altwin:swap_alt_win = +altwin(swap_alt_win)
+ + ctrlwin:swap_ctrl_win = +ctrlwin(swap_ctrl_win)
+ grp:switch = +group(switch)
+ grp:lswitch = +group(lswitch)
+ grp:win_switch = +group(win_switch)
+
+Here is the patch for evdev.lst.
+
+ --- evdev.lst.orig 2014-01-15 07:42:33.000000000 -0700
+ +++ evdev.lst 2015-01-30 20:20:20.976390083 -0700
+ @@ -800,6 +800,8 @@
+ altwin:hyper_win Hyper is mapped to Win-keys
+ altwin:alt_super_win Alt is mapped to Right Win, Super to Menu
+ altwin:swap_alt_win Alt is swapped with Win
+ + ctrlwin Ctrl/Win key behavior
+ + ctrlwin:swap_ctrl_win Ctrl and Win keys are swapped
+ Compose key Position of Compose key
+ compose:ralt Right Alt
+ compose:lwin Left Win
+
+With these changes, one can activate the option on a given X keyboard input
+device to swap the Control and Windows keys. Something like this:
+
+ setxkbmap -device 10 -option ctrlwin:swap_ctrl_win
+
+where `10` is the id of the device. One can see all the X input devices by
+running at a shell prompt:
+
+ xinput -list
+
+To de-activate the option, issue the command again but with `""` as the option
+argument. Or, since this device is a USB keyboard, simply unplug it and then
+plug it back in. At this point, we have shown the option works correctly (or
+not!) but the change is not persistent.
+
+## Step 3 -- Set the new option for the appropriate devices
+
+In Ubuntu 14.04, `/usr/share/X11/xorg.conf.d/` contains a set of files used for
+the configuration of X. Add the new file
+`/usr/share/X11/xorg.conf.d/90-evdev-CM-Storm.conf`:
+
+ Section "InputClass"
+ Identifier "CM Storm keyboard"
+ MatchIsKeyboard "on"
+ MatchDevicePath "/dev/input/event*"
+ Driver "evdev"
+ MatchUSBID "2516:0017"
+ Option "XkbOptions" "ctrlwin:swap_ctrl_win"
+ EndSection
+
+This file defines an InputClass that overrides the default for keyboards defined
+in `10-evdev.conf`. It is applicable for devices that are keyboards, whose
+device path starts with `/dev/input/event`, and shows USB VID:PID is
+`2516:0017`. The CM Storm keyboard has this VID:PID, although it's hard to
+track it down via `lsusb`. Here is the `lsusb` output on my Thinkpad:
+
+ Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
+ Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
+ Bus 001 Device 080: ID 17ef:4816 Lenovo
+ Bus 001 Device 088: ID 1366:0101 SEGGER J-Link ARM
+ Bus 001 Device 087: ID 046d:c52f Logitech, Inc. Unifying Receiver
+ Bus 001 Device 086: ID 1a40:0101 Terminus Technology Inc. 4-Port HUB
+ Bus 001 Device 085: ID 1fc9:0083 NXP Semiconductors
+ Bus 001 Device 084: ID 1058:1110 Western Digital Technologies, Inc.
+ Bus 001 Device 083: ID 1a40:0201 Terminus Technology Inc. FE 2.1 7-port Hub
+ Bus 001 Device 082: ID 046d:0825 Logitech, Inc. Webcam C270
+ Bus 001 Device 092: ID 2516:0017
+ Bus 001 Device 079: ID 17ef:1005 Lenovo
+ Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
+ Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
+
+But the Xorg log file has the information
+
+ $ grep "CM Storm.*Vendor" /var/log/Xorg.0.log.old | tail -1
+ [100514.151] (--) evdev: CM Storm Side print: Vendor 0x2516 Product 0x17
+
+## Step 4 -- Log out and back in
+
+X only reads the configurations in /usr/share/X11/xorg.conf.d on startup, so the
+X session needs to be restarted. The simplest way to do this is to log out and
+back in again. Now, upon detecting the CM Storm keyboard, its Control and
+Windows keys should be swapped without affecting any other keyboards attached to
+the system -- in my case the Thinkpad's built-in keyboard. Here's an Xorg
+snippet that shows the more specific InputClass definition working:
+
+ [101104.743] (II) config/udev: Adding input device CM Storm Side print (/dev/input/event14)
+ [101104.743] (**) CM Storm Side print: Applying InputClass "evdev keyboard catchall"
+ [101104.743] (**) CM Storm Side print: Applying InputClass "CM Storm keyboard"
+ [101104.743] (II) Using input driver 'evdev' for 'CM Storm Side print'
+ [101104.743] (**) CM Storm Side print: always reports core events
+ [101104.743] (**) evdev: CM Storm Side print: Device: "/dev/input/event14"
+ [101104.743] (--) evdev: CM Storm Side print: Vendor 0x2516 Product 0x17
+ [101104.743] (--) evdev: CM Storm Side print: Found keys
+ [101104.743] (II) evdev: CM Storm Side print: Configuring as keyboard
+ [101104.743] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.5/1-1.5.2/1-1.5.2:1.1/input/input60/event14"
+ [101104.743] (II) XINPUT: Adding extended input device "CM Storm Side print" (type: KEYBOARD, id 9)
+ [101104.744] (**) Option "xkb_rules" "evdev"
+ [101104.744] (**) Option "xkb_model" "pc105"
+ [101104.744] (**) Option "xkb_layout" "us"
+ [101104.744] (**) Option "xkb_options" "ctrlwin:swap_ctrl_win"
+
+Line three of the output shows use of the new InputClass, and the last line of
+the output above shows the xkb option applied by that class.
+
+## Step 5 -- Swap the key caps on the keyboard
+
+The CM Storm comes with a key cap puller, so it's trivial to swap the Control
+and Windows keys and have the key legends match with the new keyboard mapping.
+
+[cmstorm_img]: /image/cmstorm.jpg
+ "CM Storm Stealth image"
+
+[x201_keyboard_img]: /image/thinkpad-x201-keyboard.jpg
+ "Thinkpad X201 keyboard"
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