HID: pidff: Convert infinite length from Linux API to PID standard

Software uses 0 as de-facto infinite lenght on Linux FF apis (SDL),
Linux doesn't actually define anythi as of now, while USB PID defines
NULL (0xffff). Most PID devices do not expect a 0-length effect and
can't interpret it as infinite. This change fixes Force Feedback for
most PID compliant devices.

As most games depend on updating the values of already playing infinite
effects, this is crucial to ensure they will actually work.

Previously, users had to rely on third-party software to do this conversion
and make their PID devices usable.

Co-developed-by: Makarenko Oleg <oleg@makarenk.ooo>
Signed-off-by: Makarenko Oleg <oleg@makarenk.ooo>
Signed-off-by: Tomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>
Reviewed-by: Michał Kopeć <michal@nozomi.space>
Reviewed-by: Paul Dino Jones <paul@spacefreak18.xyz>
Tested-by: Paul Dino Jones <paul@spacefreak18.xyz>
Tested-by: Cristóferson Bueno <cbueno81@gmail.com>
Tested-by: Pablo Cisneros <patchkez@protonmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c
index 3b4ee21cd811198c7391b4855c500b67db10205d..5fe4422bb5bad0c902d508fb2faa3fccc5c4bf05 100644 (file)
--- a/drivers/hid/usbhid/hid-pidff.c
+++ b/drivers/hid/usbhid/hid-pidff.c
@@ -21,6 +21,7 @@
 #include "usbhid.h"
 
 #define        PID_EFFECTS_MAX         64
+#define        PID_INFINITE            0xffff
 
 /* Report usage table used to put reports into an array */
 
@@ -301,7 +302,12 @@ static void pidff_set_effect_report(struct pidff_device *pidff,
                pidff->block_load[PID_EFFECT_BLOCK_INDEX].value[0];
        pidff->set_effect_type->value[0] =
                pidff->create_new_effect_type->value[0];
-       pidff->set_effect[PID_DURATION].value[0] = effect->replay.length;
+
+       /* Convert infinite length from Linux API (0)
+          to PID standard (NULL) if needed */
+       pidff->set_effect[PID_DURATION].value[0] =
+               effect->replay.length == 0 ? PID_INFINITE : effect->replay.length;
+
        pidff->set_effect[PID_TRIGGER_BUTTON].value[0] = effect->trigger.button;
        pidff->set_effect[PID_TRIGGER_REPEAT_INT].value[0] =
                effect->trigger.interval;