0x8111 · latencyMonitoring

The latencyMonitoring feature provides on-device measurement and reporting of end-to-end input latency for HID++ 2.0 peripherals, most commonly high-performance gaming mice. Rather than relying on host-side timing alone, the device can measure and expose the round-trip latency between a physical input event (such as a button press or sensor sample) and the corresponding USB or wireless report reaching the host, allowing users and software to observe latency under real operating conditions. It is closely related to report-rate features such as 0x8060 adjustableReportRate and 0x8061 extendedAdjustableReportRate, since the active report rate directly affects the latencies this feature reports.

What it does

• Latency measurement — provides functions to trigger or read latency measurements recorded by the device firmware, reflecting the time from a physical input event to USB/wireless report delivery.
• Capability discovery — provides a function to query which latency measurement modes and statistics the device supports (e.g. instantaneous, average, or worst-case values).
• Mode or test control — may expose functions to start, stop, or configure a measurement session so the device enters a dedicated monitoring state separate from normal operation.
• Result retrieval — allows the host to read back collected latency statistics, which may be expressed in microseconds and broken down by phase (sensor sampling, wireless transmission, USB delivery).
• Event notifications — the device may emit asynchronous events when a new measurement result is ready or when latency crosses a configured threshold.

Status: Not implemented · Feature ID: 0x8111