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From:   Paul Jones <paul@spacefreak18.xyz>
To:     jikos@kernel.org, anssi.hannula@gmail.com
Cc:     linux-@vger.kernel.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 1/1] HID: usbhid: hid-pidff: Set Replay Length to Infinite
 when set to 0
Message-ID: <20220930225127.Horde.AdDRdase1XW5AUKNNLyXVo3@cloud.brak.space>
User-Agent: Horde Application Framework 5
Date:   Fri, 30 Sep 2022 22:51:27 +0000
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Greetings,
 
Started using my Accuforce v2 Sim wheel on Linux. I was getting no response from racing simulators through Wine, but native linux test tools worked fine. It seems that many real-world applications will send 0 as the replay length, which was resulting in the behavior I was experiencing (nothing). It makes sense to interpret 0 as an infinite effect and therefore set the replay length of the effect to 0xffff. While the PID document does not explicitly state that 0 should be infinite, it does hint toward null values being interpreted as infinite.
 
---
 
diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c
index 3b4ee21cd811..70653451c860 100644
--- a/drivers/hid/usbhid/hid-pidff.c
+++ b/drivers/hid/usbhid/hid-pidff.c
@@ -301,7 +301,7 @@ 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;
+ pidff->set_effect[PID_DURATION].value[0] = effect->replay.length == 0 ? 0xffff : 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;
 
-- 
 
- Paul