Support for Microsoft Sidewinder FF2

[HiranChaudhuri]

While I can use my Microsoft Sidewinder FF2 joystick as a normal joystick in Linux (all axes and buttons work as expected), force feedback seems to just not exist.

Trying to understand both https://docs.kernel.org/input/joydev/joystick.html#microsoft-sidewinder-joysticks and https://docs.kernel.org/input/ff.html the joystick should be supported but I cannot make it work.

Which /dev/input/eventXX file should I use when running fftest?
Why does fftest /dev/input/event0 (and all the other event files I have available) always tell me that functions are not implemented?
With that, my joystick will always behave like a standard joystick with just centering forces.

$ fftest /dev/input/event0 
Force feedback test program.
HOLD FIRMLY YOUR WHEEL OR JOYSTICK TO PREVENT DAMAGES

Device /dev/input/event0 opened
Features:
  * Absolute axes: 
    [00 00 00 00 00 00 00 00 ]
  * Relative axes: 
    [00 00 ]
  * Force feedback effects types: 
    Force feedback periodic effects: 
    [00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ]
  * Number of simultaneous effects: 0

Uploading effect #0 (Periodic sinusoidal) ... Error:: Function not implemented
Uploading effect #1 (Constant) ... Error: Function not implemented
Uploading effect #2 (Spring) ... Error: Function not implemented
Uploading effect #3 (Damper) ... Error: Function not implemented
Uploading effect #4 (Strong rumble, with heavy motor) ... Error: Function not implemented
Uploading effect #5 (Weak rumble, with light motor) ... Error: Function not implemented
Enter effect number, -1 to exit

[HiranChaudhuri]

The list of joysticks actually does not cover the FF2 directly. While at the beginning I did not worry, maybe this is exactly the issue.

$ lsusb
...
Bus 001 Device 007: ID 045e:001b Microsoft Corp. SideWinder Force Feedback 2 Joystick
...
$

I downloaded https://cdn.kernel.org/pub/linux/kernel/v6.x/linux-6.1.6.tar.xz and searched for the file linux-6.1.6/drivers/input/joystick/sidewinder.c. Inside there you find the list of supported devices:

static char *sw_name[] = {	"3D Pro", "GamePad", "Precision Pro", "Force Feedback Pro", "FreeStyle Pro",
				"Force Feedback Wheel" };

The list is in sync with the one on https://docs.kernel.org/input/joydev/joystick.html#microsoft-sidewinder-joysticks.
But the Force Feedback 2 is not mentioned at all. :-(

[HiranChaudhuri]

Sad it was no part of the documentation I mentioned above.
It is important to have write access to the /dev/input/eventXX files. Which of them exactly depends on which of them is your joystick. You can run the command evtest to figure out the correct file.

Once there, run fftest and this is where I felt the joystick rumble.

It works, after all.

[twhitehead]

I just use

ls -l /dev/input/by-id

...
lrwxrwxrwx 1 root root 10 Dec 25 17:26 usb-Microsoft_SideWinder_Force_Feedback_2_Joystick-event-joystick -> ../event22
lrwxrwxrwx 1 root root  6 Dec 25 17:26 usb-Microsoft_SideWinder_Force_Feedback_2_Joystick-joystick -> ../js2
...

[HiranChaudhuri]

That is a really smart way to identify the correct device. I love it!
But that just proves it should be documented somewhere.