HID: pidff: Add MISSING_PBO quirk and its detection

Some devices with only one axis are missing PARAMETER_BLOCK_OFFSET field
for conditional effects. They can only have one axis, so we're limiting
the max_axis when setting the report for those effects.

Automatic detection ensures compatibility even if such device won't be
explicitly defined in the kernel.

Fixes initialization of VRS DirectForce PRO and possibly other devices.

Changes in v6:
- Fixed NULL pointer dereference. When PBO is missing, make sure not
  to set it anyway

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>

Author: Lawstorant

drivers/hid/usbhid/hid-pidff.c

@@ -404,13 +404,19 @@ static int pidff_needs_set_periodic(struct ff_effect *effect,
 static void pidff_set_condition_report(struct pidff_device *pidff,
 				       struct ff_effect *effect)
 {
-	int i;
+	int i, max_axis;
+
+	/* Devices missing Parameter Block Offset can only have one axis */
+	max_axis = pidff->quirks & HID_PIDFF_QUIRK_MISSING_PBO ? 1 : 2;
 
 	pidff->set_condition[PID_EFFECT_BLOCK_INDEX].value[0] =
 		pidff->block_load[PID_EFFECT_BLOCK_INDEX].value[0];
 
-	for (i = 0; i < 2; i++) {
-		pidff->set_condition[PID_PARAM_BLOCK_OFFSET].value[0] = i;
+	for (i = 0; i < max_axis; i++) {
+		/* Omit Parameter Block Offset if missing */
+		if (!(pidff->quirks & HID_PIDFF_QUIRK_MISSING_PBO))
+			pidff->set_condition[PID_PARAM_BLOCK_OFFSET].value[0] = i;
+
 		pidff_set_signed(&pidff->set_condition[PID_CP_OFFSET],
 				 effect->u.condition[i].center);
 		pidff_set_signed(&pidff->set_condition[PID_POS_COEFFICIENT],
@@ -822,6 +828,11 @@ static int pidff_find_fields(struct pidff_usage *usage, const u8 *table,
 			pr_debug("Setting MISSING_DELAY quirk\n");
 			return_value |= HID_PIDFF_QUIRK_MISSING_DELAY;
 		}
+		else if (!found && table[k] == pidff_set_condition[PID_PARAM_BLOCK_OFFSET]) {
+			pr_debug("PBO field not found, but that's OK\n");
+			pr_debug("Setting MISSING_PBO quirk\n");
+			return_value |= HID_PIDFF_QUIRK_MISSING_PBO;
+		}
 		else if (!found && strict) {
 			pr_debug("failed to locate %d\n", k);
 			return -1;
@@ -1101,7 +1112,6 @@ static int pidff_find_effects(struct pidff_device *pidff,
  */
 static int pidff_init_fields(struct pidff_device *pidff, struct input_dev *dev)
 {
-	int envelope_ok = 0;
 	int status = 0;
 
 	/* Save info about the device not having the DELAY ffb field. */
@@ -1132,13 +1142,10 @@ static int pidff_init_fields(struct pidff_device *pidff, struct input_dev *dev)
 		return -ENODEV;
 	}
 
-	if (!PIDFF_FIND_FIELDS(set_envelope, PID_SET_ENVELOPE, 1))
-		envelope_ok = 1;
-
 	if (pidff_find_special_fields(pidff) || pidff_find_effects(pidff, dev))
 		return -ENODEV;
 
-	if (!envelope_ok) {
+	if (PIDFF_FIND_FIELDS(set_envelope, PID_SET_ENVELOPE, 1)) {
 		if (test_and_clear_bit(FF_CONSTANT, dev->ffbit))
 			hid_warn(pidff->hid,
 				 "has constant effect but no envelope\n");
@@ -1163,16 +1170,20 @@ static int pidff_init_fields(struct pidff_device *pidff, struct input_dev *dev)
 		clear_bit(FF_RAMP, dev->ffbit);
 	}
 
-	if ((test_bit(FF_SPRING, dev->ffbit) ||
-	     test_bit(FF_DAMPER, dev->ffbit) ||
-	     test_bit(FF_FRICTION, dev->ffbit) ||
-	     test_bit(FF_INERTIA, dev->ffbit)) &&
-	    PIDFF_FIND_FIELDS(set_condition, PID_SET_CONDITION, 1)) {
-		hid_warn(pidff->hid, "unknown condition effect layout\n");
-		clear_bit(FF_SPRING, dev->ffbit);
-		clear_bit(FF_DAMPER, dev->ffbit);
-		clear_bit(FF_FRICTION, dev->ffbit);
-		clear_bit(FF_INERTIA, dev->ffbit);
+	if (test_bit(FF_SPRING, dev->ffbit) ||
+	    test_bit(FF_DAMPER, dev->ffbit) ||
+	    test_bit(FF_FRICTION, dev->ffbit) ||
+	    test_bit(FF_INERTIA, dev->ffbit)) {
+		status = PIDFF_FIND_FIELDS(set_condition, PID_SET_CONDITION, 1);
+
+		if (status < 0) {
+			hid_warn(pidff->hid, "unknown condition effect layout\n");
+			clear_bit(FF_SPRING, dev->ffbit);
+			clear_bit(FF_DAMPER, dev->ffbit);
+			clear_bit(FF_FRICTION, dev->ffbit);
+			clear_bit(FF_INERTIA, dev->ffbit);
+		}
+		pidff->quirks |= status;
 	}
 
 	if (test_bit(FF_PERIODIC, dev->ffbit) &&

include/linux/hid.h

@@ -1230,6 +1230,7 @@ int hid_pidff_init(struct hid_device *hid);
 
 /* HID PIDFF quirks */
 #define HID_PIDFF_QUIRK_MISSING_DELAY	BIT(0)
+#define HID_PIDFF_QUIRK_MISSING_PBO	BIT(1)
 
 #define dbg_hid(fmt, ...) pr_debug("%s: " fmt, __FILE__, ##__VA_ARGS__)