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Commit 634b15ad authored by Tomasz Pakuła's avatar Tomasz Pakuła Committed by Greg Kroah-Hartman
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HID: pidff: Do not send effect envelope if it's empty 



[ Upstream commit 8876fc1884f5b39550c8387ff3176396c988541d ]

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: default avatarTomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>
Reviewed-by: default avatarMichał Kopeć <michal@nozomi.space>
Reviewed-by: default avatarPaul Dino Jones <paul@spacefreak18.xyz>
Tested-by: default avatarPaul Dino Jones <paul@spacefreak18.xyz>
Tested-by: default avatarCristóferson Bueno <cbueno81@gmail.com>
Tested-by: default avatarPablo Cisneros <patchkez@protonmail.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 85123a58

drivers/hid/usbhid/hid-pidff.c

+24 −18
Original line number Diff line number Diff line
@@ -262,6 +262,18 @@ static void pidff_set_envelope_report(struct pidff_device *pidff, 
static int pidff_needs_set_envelope(struct ff_envelope *envelope,

				    struct ff_envelope *old)

{

	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 ||
@@ -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: