From 8876fc1884f5b39550c8387ff3176396c988541d Mon Sep 17 00:00:00 2001 From: =?utf8?q?Tomasz=20Paku=C5=82a?= Date: Sat, 1 Feb 2025 12:38:46 +0100 Subject: [PATCH] HID: pidff: Do not send effect envelope if it's empty MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Envelope struct is always initialized, but the envelope itself is optional as described in USB PID Device class definition 1.0. 5.1.1.1 Type Specific Block Offsets ... 4) Effects that do not use Condition Blocks use 1 Parameter Block and an *optional* Envelope Block. Sending out "empty" envelope breaks force feedback on some devices with games that use SINE effect + offset to emulate constant force effect, as well as generally breaking Constant/Periodic effects. One of the affected brands is Moza Racing. This change prevents the envelope from being sent if it contains all 0 values while keeping the old behavior of only sending it, if it differs from the old one. Changes in v6: - Simplify the checks to make them clearer - Fix possible null pointer dereference while calling pidff_needs_set_envelope Signed-off-by: Tomasz Pakuła Reviewed-by: Michał Kopeć Reviewed-by: Paul Dino Jones Tested-by: Paul Dino Jones Tested-by: Cristóferson Bueno Tested-by: Pablo Cisneros Signed-off-by: Jiri Kosina --- drivers/hid/usbhid/hid-pidff.c | 42 +++++++++++++++++++--------------- 1 file changed, 24 insertions(+), 18 deletions(-) diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c index 5fe4422bb5ba..a01c1b2ab2f4 100644 --- a/drivers/hid/usbhid/hid-pidff.c +++ b/drivers/hid/usbhid/hid-pidff.c @@ -262,10 +262,22 @@ static void pidff_set_envelope_report(struct pidff_device *pidff, static int pidff_needs_set_envelope(struct ff_envelope *envelope, struct ff_envelope *old) { - return envelope->attack_level != old->attack_level || - envelope->fade_level != old->fade_level || + bool needs_new_envelope; + needs_new_envelope = envelope->attack_level != 0 || + envelope->fade_level != 0 || + envelope->attack_length != 0 || + envelope->fade_length != 0; + + if (!needs_new_envelope) + return false; + + if (!old) + return needs_new_envelope; + + return envelope->attack_level != old->attack_level || + envelope->fade_level != old->fade_level || envelope->attack_length != old->attack_length || - envelope->fade_length != old->fade_length; + envelope->fade_length != old->fade_length; } /* @@ -580,11 +592,9 @@ static int pidff_upload_effect(struct input_dev *dev, struct ff_effect *effect, pidff_set_effect_report(pidff, effect); if (!old || pidff_needs_set_constant(effect, old)) pidff_set_constant_force_report(pidff, effect); - if (!old || - pidff_needs_set_envelope(&effect->u.constant.envelope, - &old->u.constant.envelope)) - pidff_set_envelope_report(pidff, - &effect->u.constant.envelope); + if (pidff_needs_set_envelope(&effect->u.constant.envelope, + old ? &old->u.constant.envelope : NULL)) + pidff_set_envelope_report(pidff, &effect->u.constant.envelope); break; case FF_PERIODIC: @@ -619,11 +629,9 @@ static int pidff_upload_effect(struct input_dev *dev, struct ff_effect *effect, pidff_set_effect_report(pidff, effect); if (!old || pidff_needs_set_periodic(effect, old)) pidff_set_periodic_report(pidff, effect); - if (!old || - pidff_needs_set_envelope(&effect->u.periodic.envelope, - &old->u.periodic.envelope)) - pidff_set_envelope_report(pidff, - &effect->u.periodic.envelope); + if (pidff_needs_set_envelope(&effect->u.periodic.envelope, + old ? &old->u.periodic.envelope : NULL)) + pidff_set_envelope_report(pidff, &effect->u.periodic.envelope); break; case FF_RAMP: @@ -637,11 +645,9 @@ static int pidff_upload_effect(struct input_dev *dev, struct ff_effect *effect, pidff_set_effect_report(pidff, effect); if (!old || pidff_needs_set_ramp(effect, old)) pidff_set_ramp_force_report(pidff, effect); - if (!old || - pidff_needs_set_envelope(&effect->u.ramp.envelope, - &old->u.ramp.envelope)) - pidff_set_envelope_report(pidff, - &effect->u.ramp.envelope); + if (pidff_needs_set_envelope(&effect->u.ramp.envelope, + old ? &old->u.ramp.envelope : NULL)) + pidff_set_envelope_report(pidff, &effect->u.ramp.envelope); break; case FF_SPRING: -- 2.50.1