.. |version| replace:: 0.3.0 .. |date| date:: ======= marsond ======= ---------------------------------------------------------------- Fix Enter key timing on Marson/USBLink/MT606-1 PS/2-USB adaptors ---------------------------------------------------------------- :Manual section: 8 :Manual group: Urchlay's Stuff :Date: |date| :Version: |version| SYNOPSIS ======== marsond [**-d** *delay-ms**] [**-f**] [**-k** *keyboard-device*] [**-p** *pause_ms* [**-v**] | [**--help**] | [**--version**] | [**-V**] DESCRIPTION =========== **marsond** fixes an issue with a particular model of PS/2 => USB keyboard adaptor. The symptom: in games and emulators, the Enter key only works sometimes. This is caused by the firmware in the adaptor sending the keypress and release events only 8 milliseconds apart. The problem happens with any SDL application (SDL1 or SDL2), as well as other graphics libraries. It happens regardless of what PS/2 keyboard you have plugged in, what computer you have the adaptor plugged into, or what OS that computer is running. The specific hardware that has the Enter key problem for me is USB vendor ID 04b4, product ID 0101, "Marson Keyboard and Mouse Link Ver:ps2120L". It has a label on the front that says "USBLink", and on the back, the model number is "MT606-1". It looks like: https://slackware.uk/~urchlay/sdl-usblink-hack/marson-front.jpg https://slackware.uk/~urchlay/sdl-usblink-hack/marson-back.jpg I'm not sure if any other USB keyboard adaptors are affected. If you have the problem on some other adaptor, and **marsond** fixes it, please contact me so I can add the model number to this man page. **marsond** uses the Linux kernel's **uinput** layer to "grab" the keyboard, create a new virtual keyboard device, and pass events from the real keyboard to the virtual one. When it sees the key release event for the Enter key, it simply pauses for a few milliseconds before delivering it. This should work with everything that uses the keyboard. It definitely does, with SDL 1 and 2 running under X (and SDL 1 on the console, too). I don't use Wayland, so I haven't tested it there. If you do, please contact me and let me know if it works for you. For normal use, **marsond** will be started by a **udev**\(7) rule when the adaptor is plugged in (including booting with the adaptor connected). The udev rule is found in: /etc/udev/rules.d/99-marsond.rules ...which can be edited to change the options it's run with, if needed. The defaults work well on the author's system. **marsond** must be run as root. At startup, it does these things as root: - Grab the physical keyboard. - Create the virtual keyboard device. - Lock its pages into physical memory, to avoid being swapped out. - Set its priority (nice value) to -20 (highest priority), to avoid slow response on a loaded system. After doing the above, root access is no longer needed, so it will drop privileges and run as the *nobody* user by default (but see **ENVIRONMENT** if you need a different user). While **marsond** is running, "xinput --list" will show an input device called "marson virtual keyboard". OPTIONS ======= Options can be "bundled": **-vf** is the same as **-v** **-f**. -d delay-ms Amount of time in milliseconds to delay the Enter key release events. Default: 30. .. delay time for Enter key relase (default 30). -f Run in the foreground; do not detach from the terminal or become a daemon. In this mode, **marsond** can be killed with *^C*. .. run in foreground, not as a daemon. -k keyboard-device Input device for the keyboard adaptor. Default: /dev/input/by-id/usb-Marson_Marson_Keyboard_and_Mouse_Link_Ver:ps2120L-event-kbd .. keyboard device (usually under /dev/input/by-id/). -p pause-ms Amount of time in milliseconds to pause at startup, before opening the keyboard and uinput devices. May be useful on slow systems, if **marsond** won't consistently start from udev, but works fine if started manually. Default: 0. .. pause before opening keyboard/uinput devs (default 0). -v Verbose debugging mode. Prints copious trace information to **stderr**. Debugging mode is turned off when **marsond** forks itself into the background as a daemon. If you want to debug the event loop, combine **-v** and **-f**. .. verbose debugging. -h, --help Shows built-in usage message and exits. .. this help text. -V, --version Shows version number and exits. .. show version number. ENVIRONMENT =========== MARSOND_USER After initialization, **marsond** will drop privileges by setting its user ID to this user's. Default: *nobody* MARSOND_GROUP Group to run as, after dropping privileges. Default: the primary group of the user it's running as. Normally you won't have to set this. LIMITATIONS =========== Only one MT-606-1 device is supported, out of the box. This shouldn't really be a problem (do you really need 2 keyboards?) but it's worth mentioning. If you really do own two of these adaptors and want to use them on the same PC, you could add a second udev rule (with -k option for the daemon). This isn't really a **marsond** problem per se, but when Xorg detects a new keyboard, it resets your keyboard repeat rate (**xset r**) and custom keymap (**xmodmap**\(1)). If you use a 'desktop' such as KDE, GNOME, or XFCE, it should re-apply your settings. For a traditional window manager (WindowMaker, FVWM2, etc), this can be very annoying. .. EXIT STATUS .. =========== .. BUGS .. ==== .. EXAMPLES .. ======== COPYRIGHT ========= WTFPL. Short version: do WTF you want. Full version: http://www.wtfpl.net/txt/copying/ AUTHORS ======= B. Watson SEE ALSO ======== The homepage: https://slackware.uk/~urchlay/repos/marsond Another solution to the problem, less complete, but should be portable to non-Linux OSes: https://slackware.uk/~urchlay/sdl-usblink-hack/