linux-kernel - [PATCH 08/10] HID: pidff: Add FIX_WHEEL

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Message-ID: <20241231154731.1719919-9-tomasz.pakula.oficjalny@gmail.com>
Date: Tue, 31 Dec 2024 16:47:29 +0100
From: Tomasz Pakuła <tomasz.pakula.oficjalny@...il.com>
To: jikos@...nel.org,
	bentiss@...nel.org
Cc: linux-kernel@...r.kernel.org,
	linux-usb@...r.kernel.org,
	oleg@...arenk.ooo,
	paul@...cefreak18.xyz,
	f.kardame@...jaro.org,
	jules.noirant@...nge.fr
Subject: [PATCH 08/10] HID: pidff: Add FIX_WHEEL_DIRECTION quirk

Most steering wheels simply ignore DIRECTION field, but some try to be
compliant with the PID standard and use it in force calculations. Games
often ignore setting this field properly and/or there can be issues with
dinput8 -> SDL -> Linux API translation, and this value can be incorrect.
This can lead to partial/complete loss of Force Feedback or even
unexpected force reversal.

Sadly, this quirk can't be detected automatically without sending out
effects that would move an axis.

This fixes FFB on Moza Racing devices and others where effect direction
is not simply ignored.

Signed-off-by: Tomasz Pakuła <tomasz.pakula.oficjalny@...il.com>
---
 drivers/hid/usbhid/hid-pidff.c | 12 +++++++++---
 include/linux/hid.h            |  1 +
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c
index c919e2db8dc0..cc02c5d1bd04 100644
--- a/drivers/hid/usbhid/hid-pidff.c
+++ b/drivers/hid/usbhid/hid-pidff.c
@@ -136,6 +136,9 @@ static const u8 pidff_block_load_status[] = { 0x8c, 0x8d };
 #define PID_EFFECT_STOP		1
 static const u8 pidff_effect_operation_status[] = { 0x79, 0x7b };
 
+/* Polar direction 90 degrees (North) */
+#define PIDFF_FIXED_WHEEL_DIRECTION	0x4000
+
 struct pidff_usage {
 	struct hid_field *field;
 	s32 *value;
@@ -354,9 +357,12 @@ static void pidff_set_effect_report(struct pidff_device *pidff,
 	pidff->set_effect[PID_GAIN].value[0] =
 		pidff->set_effect[PID_GAIN].field->logical_maximum;
 	pidff->set_effect[PID_DIRECTION_ENABLE].value[0] = 1;
-	pidff->effect_direction->value[0] =
-		pidff_rescale(effect->direction, 0xffff,
-				pidff->effect_direction);
+
+	// Use fixed direction if needed
+	pidff->effect_direction->value[0] = pidff_rescale(
+		pidff->quirks & HID_PIDFF_QUIRK_FIX_WHEEL_DIRECTION ?
+		PIDFF_FIXED_WHEEL_DIRECTION : effect->direction,
+		0xffff, pidff->effect_direction);
 
 	// Omit setting delay field if it's missing
 	if (!(pidff->quirks & HID_PIDFF_QUIRK_MISSING_DELAY))
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 93233c5b75a6..5237f9040950 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -1233,6 +1233,7 @@ int hid_pidff_init_with_quirks(struct hid_device *hid, __u32 initial_quirks);
 #define HID_PIDFF_QUIRK_MISSING_DELAY		BIT(0)
 #define HID_PIDFF_QUIRK_MISSING_PBO		BIT(1)
 #define HID_PIDFF_QUIRK_MISSING_DEVICE_CONTROL	BIT(2)
+#define HID_PIDFF_QUIRK_FIX_WHEEL_DIRECTION	BIT(3)
 
 #define dbg_hid(fmt, ...) pr_debug("%s: " fmt, __FILE__, ##__VA_ARGS__)
 
-- 
2.47.1