Joystick support

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Contents

Howto

About Joysticks

Most older joysticks come with a so-called game port connector (15 pins SUB-D) and can be connected with the game port of the sound card.

Newer joysticks typically use USB and therefore do not need any ALSA/soundcard support.

How can I enable game port support in ALSA?

Make sure the kernel module handling your sound card has game port support enabled. Many modules disable the game port by default. See /usr/src/Documentation/sound/alsa/Joystick.txt for a list of options. lsmod/modinfo might also help.

Make sure the joystick is plugged in when loading the modules as some modules disable the game port if they do not find a joystick connected.

Technically, game port functionality is implemented by the gameport kernel module (which the sound card module depends on). Then, there are modules for each type of joystick (e.g., analog/sidewinder/...). The /dev/input/jsX device is backed by the joydev kernel module.

For old ISA sound cards, you need the ns558 module instead of gameport.

Module options typically go into /etc/modutils/ for Linux 2.4.x (run update-modules afterwards to generate modules.conf, syntax see man modules.conf) or /etc/modprobe.d/ for Linux 2.6.x (see man modprobe.d). Make sure you're not changing obsolete configuration files that are not used by modprobe anyways. Test using modprobe -vn MODULE (when the respective module is not loaded).

ALSA supported enabling/disabling the game port using the ALSA control API (i.e., alsactl) in the past. However, for Linux 2.6.7 and newer, only static initialization using module parameters is supported.

For special setups (e.g., two two-axis joysticks on one game port using a Y cable) see parameters of your joystick module (e.g., analog).

Troubleshooting

Discussion

snd-ens1370 vs. ns558

This doesn't seem to do the trick. I am using the ens-1370 module and devfs. When I do insmod joydev and insmod analog js=gameport I don't get a js0 anywhere in /dev. What else needs to be done?

You need to load the module ns558:

modprobe ns558
modprobe gameport
modprobe sidewinder

The modprobe sidewinder is for my MS SW gamepad; change it to the correct module for your own joystick/gamepad. From /var/log/syslog, you will get something like:

Oct 28 23:56:05 void kernel: gameport0: NS558 ISA at 0x200 size 8 speed 1065 kHz
Oct 28 23:56:34 void kernel: input1: Microsoft SideWinder GamePad on gameport0.0

I just spent several hours figuring out that you need to have a joystick connected, for ns558 to positively identify the port. ns558 does some magic to identify the I/O address, which relies on a joystick being connected. Check out the source code. If you think that is obvious, it isn't if you want to use the gameport to read a few bits from external hardware (which may or may not be connected). If you are just interested in the button lines, you can connect some resistors between the lines for the pots and +5V. There is some good information here. Something else that is confusing is that there are lots of documents out there on the web that talk about es1371, as opposed to snd-ens1371. Before you go crazy, make sure that you are really looking at the relevant module, not something vaguely related from a previous incarnation of the kernel, like I did for a while.

User:1370: I use snd-ens1370 with gameport but no ns558 on Linux 2.6.19. AFAIK es1370/es1371 is OSS, not ALSA. Avoid that driver.

via82xx onboard gameport

For the via82xx onboard gameport (might be relevant to other hw):

Now you only have to modprobe the driver for the actual joystick/pad (in my case grip for a Gravis GamePad Pro). The gameport driver (gameport.[k]o) seems to get automatically loaded with the via82xx driver.

Ens1370 soundcard and alsactl

I had the joystick working fine in kernel 2.4.19 and 2.6.0 using alsa and an ens1370 soundcard. Joystick support was broken when I upgraded to 2.6.7, 2.6.8 and 2.6.10. Deleting /var/lib/asound.state and running "alsactl store 0" to create a new /var/lib/asound.state would, with kernels 2.4.19 and 2.6.0, create an asound.state with a control.1 entry for the joystick. I could then edit this control and run "alsactl restore 0" to turn the joystick on or off. With kernels 2.6.7 and later the joystick option was missing. It appears that editing "asound.state" to enable/disable the joystick is no longer an option with the latest kernels.

To get the joystick working in kernel 2.6.10 (Debian) I had to do the following:

​1. I compiled a kernel with the gameport module compiled in. The ens1370 module (and other alsa modules with joystick support) require the gameport module to be either compiled in or as a module, otherwise they don't compile with joystick support. To be safe I built it into the kernel. I didn't try building gameport as a module, but this might work as well. YMMV.

​2. Edit /etc/alsa/modutils/1.0 such that it had the following two lines: This causes the command cat /proc/asound/card0/audiopci (in my case, with the ens1370 card) to show that the joystick is enabled, provided that step 3 is added to ensure that the modules are loaded in the correct order:

alias snd-card-0 snd-ens1370
options snd-ens1370 joystick=1

​3. /etc/modutils/joystick should be as follows: (Note: the line "pre-install snd-ens1370 modprobe analog" may not be necessary.)

alias char-major-13 analog
pre-install snd-ens1370 modprobe analog
pre-install analog modprobe joydev

​4. The file "/etc/modules" should have the following lines (among any other modules you want installed):

joydev
analog

​5. Run "update-modules" to update "/etc/modules.conf".

Note: For kernel 2.6.7 and later the module ns558 (or any other than analog and joydev) is not required if you're using one of the soundcards that has joystick support built-in (at least this is the case with the ens1370). See the kernel config for details. In my case, the driver configured itself as /dev/input/js0. If you were previously using /dev/js0 or /dev/js this will need to be changed. Note: For me, the joystick worked in 2.4.19 and 2.6.0. In 2.6.7 and later it was broken (until the preceding steps fixed it). I don't know what the situation is in the kernel versions between 2.6.0 and 2.6.7.

User:1370: ALSA kernel docs (joystick.txt) say that alsactl/asound.state functionality for enabling/disabling gameports was dropped quite a while ago. BTW /etc/modutils is Linux 2.4.x, use /etc/modprobe.d/ for Linux 2.6.x.

Centos4

I finally got this to work on centos4. Took all day.

  1. Recompile your kernel to turn on analog.ko and gameport.ko
  2. With 1370 it's joystick=1 with 1371 it's joystick_port=1
  3. There is a several second delay between the module loading and js0 showing up. If you modprobe then ls /dev/input too fast you won't see it there yet.
  4. It's very very very picky.
  5. I had to completely disable my onboard via82xx sound, in the CMOS and in modprobe.conf.
  6. alias snd-card-0 snd-ens1371, then options snd-card-0 joystick(_port)=1 didn't seem to work, not sure. I made it explicit.
  7. gameport can be a module.
  8. Did I mention this whole thing is very flaky?

Working modprobe.conf for 1370/1371 is below, for 1370 just change all references and also joystick_port becomes joystick:

alias snd-card-0 snd-ens1371
alias char-major-13 analog
options snd-ens1371 joystick_port=1
install snd-ens1371 /sbin/modprobe -i joydev; \
 /sbin/modprobe -i analog; \
 /sbin/modprobe --ignore-install snd-ens1371; \
 /usr/sbin/alsactl restore;
remove snd-ens1371 { /usr/sbin/alsactl store >/dev/null 2>&1 || : ; }; \
 /sbin/modprobe -r --ignore-remove snd-ens1371

Retrieved from "http://alsa.opensrc.org/Joystick_support"

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