The bundled SDL was configured with SDL_HIDAPI OFF, so a DualSense went
through the generic joystick driver of the platform: no touchpad, no
light bar and no DualSense effect reports, which left the light bar,
trigger effect and (on Linux) rumble requests that PadInput already
sends through SDL without effect on the controller. With HIDAPI, SDL's
PS5 driver handles the pad: touchpad, light bar, rumble, trigger effects
and the motion sensors.
A USB pad always uses the driver's enhanced reports.
SDL_HINT_JOYSTICK_HIDAPI_PS5_RUMBLE enables them for a Bluetooth pad as
well, which otherwise stays on the simple report without effects.
pad_sdl checks that the bundled SDL is built with the HIDAPI joystick
driver.
Dean Galvin