Force-feedback is not properly advertised when enabled

[RalfJung]

It seems like xboxdrv does not properly advertise supporting force-feedback even when it is enabled. As a result, Windows programs executed via wine think the gamepad does not support force feedback, and do not use it. Also see https://bugs.winehq.org/show_bug.cgi?id=33522.

[00cpxxx]

To clarify the source code side, wine does:

ioctl(fd, EVIOCGBIT(0, sizeof(joydev.evbits)), joydev.evbits); //get feature bits
test_bit(joydev.evbits, EV_FF) //check if FF was advertised
ioctl(fd, EVIOCGBIT(EV_FF, sizeof(joydev.ffbits)), joydev.ffbits) //read FF supported effect bits
ioctl(fd, EVIOCGEFFECTS, &joydev.num_effects) // read number of effects
joydev.num_effects > 0 //ensure at least 1 effect is supported

At some point there is a failure in a step and Wine gives up FF for the device. The code starts around [1], FF checks are around line 284.

[1] https://source.winehq.org/source/dlls/dinput/joystick_linuxinput.c#0218