0x19b0 · hapticFeedback – OpenLogi Docs

Device haptic actuator control — capabilities, enable state and intensity, and playing a typed waveform, as used by the MX Master 4's Actions Ring.

Controls a device's haptic actuator: which waveforms it can play, whether haptics are enabled and at what intensity, and playing one waveform immediately.

OpenLogi uses it for the Actions Ring on the MX Master 4, a subtle pulse when the highlighted slot changes, and a firmer one when an action runs.

Logitech has not published this feature in the public HID++ spec. The function and payload layouts here were cross-checked against Solaar and an MX Master 4; additions must be verified against hardware rather than guessed.

Spec: reverse-engineered — x19b0 hapticFeedback. Used by: Actions Ring hover and activation feedback.

Function reference

The HapticFeedbackFeature wrapper (0x19b0) exposes:

Methods

Function	HID++ fn	Signature	Returns
`get_capabilities`	0	`()`	`HapticCapabilities`
`get_configuration`	1	`()`	`HapticConfiguration`
`set_configuration`	2	`(enabled: bool, intensity: HapticIntensity)`	`()`
`play`	4	`(waveform: HapticWaveform)`	`()`

All are async and return Result<…, Hidpp20Error>.

Types

`HapticCapabilities`

Field	Type	Description
`unknown_prefix`	`[u8; 4]`	Bytes whose meaning has not yet been verified.
`waveforms`	`SupportedWaveforms`	Supported waveform mask.

`SupportedWaveforms`

A bitflags mask; unknown bits are retained so newer firmware doesn't silently lose capability information.

Flag	Bit	Description
`DAMP_STATE_CHANGE`	1	A damp state-change pulse, used after activating a ring action.
`SUBTLE_COLLISION`	4	A subtle collision pulse, used when the highlighted ring slot changes.

`HapticWaveform`

Variant	Value	Description
`DampStateChange`	1	Confirmation pulse used when an action runs.
`SubtleCollision`	4	Light boundary pulse used for hover transitions.

`HapticConfiguration`

Field	Type	Description
`enabled`	`bool`	Whether firmware haptic playback is enabled.
`intensity`	`HapticIntensity`	Current intensity percentage.
`level_count`	`u8`	Number of discrete levels advertised by the firmware.
`level_step`	`u8`	Percentage step between discrete levels.

`HapticIntensity`

A validated 0–100 percentage: HapticIntensity::new(value) returns None above HapticIntensity::MAX (100), so an out-of-range intensity can never reach the wire.

Wire format

Function	Request	Response
0 `get_capabilities`	`[0x00, 0x00, 0x00]`	bytes 0–3 unverified prefix; bytes 4–7 big-endian `u32` waveform mask
1 `get_configuration`	`[0x00, 0x00, 0x00]`	byte 0 enabled (`0`/`1`); byte 1 intensity percent; byte 2 high nibble = level step, low nibble = level count
2 `set_configuration`	`[enabled, intensity, 0x00]`	—
4 `play`	`[waveform, 0x00, 0x00]`	—

An enabled byte other than 0/1, or an intensity above 100, fails as Hidpp20Error::UnsupportedResponse rather than being coerced.

Usage (Rust)

use hidpp::{
    device::Device,
    feature::haptic_feedback::{HapticFeedbackFeature, HapticIntensity, HapticWaveform},
};

// device: &mut Device, already created via Device::new(channel, index)
device.enumerate_features().await?;

if let Some(feat) = device.get_feature::<HapticFeedbackFeature>() {
    let caps = feat.get_capabilities().await?;
    println!("waveforms: {:?}", caps.waveforms);

    if let Some(intensity) = HapticIntensity::new(60) {
        feat.set_configuration(true, intensity).await?;
    }
    feat.play(HapticWaveform::SubtleCollision).await?;
}

0x19b0 · hapticFeedback

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