[Bug 51922] HID joystick constant Force Feedback effect does not work

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=51922

--- Comment #14 from Ivo Ivanov <logos128 at gmail.com> ---
Created attachment 71221
  --> https://bugs.winehq.org/attachment.cgi?id=71221
winebus-fixes.patch

I remember that comment in the SDL code :)
I got confused by it when I was writing a Linux FFB driver for a Fanatec device
and found it on the net. Maybe they mean the 90 deg difference between polar
and spherical. Anyway, it is visible from the SDL code that they just rescale
the source polar coords to the Linux FF range.

So your previous code was correct. I have reverted the lnxev part of the patch,
and immediately the "set effect" output reports started showing the correct
direction 0x2d similar to the other backends and Windows.

The FFB was still absent, though, so I looked at some captured usb traffic, and
found two interesting things. The FF gain was set to 0 on the lnxev backend,
and the duration field of the "set effect" report was 0x7fff on the both SDL
and lnxev backends.

For the first issue appeared that FF_GAIN needed to be rescaled for the Linux
FF range.

For the second issue, we pass correctly 0xffff for infinite duration, but Linux
just clamps it to the max allowed value of 0x7fff, as it doesn't consider that
value an infinite duration. The Linux FF uses 0 for that, while SDL uses
SDL_HAPTIC_INFINITY.

So, attached patches that correct the issues. Tested thoroughly both the SDL
and lnxev backends with various games - rFactor 2, Assetto Corsa Competizione,
Automobilista 2, BeamNG, etc. The FFB worked properly and on par with hidraw
and Windows.
The only problem I could still spot is that the damper condition effect is very
weak in comparison to hidraw and Windows. Assetto Corsa Competizione uses such
effect when the car is stand still.

The patches are based on 3f6102080e632b9f4d8a97c0f0b1231fbd8e759b

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