REQ-NF-PEV2-001: Real-Time Safety - No Blocking Calls in PEv2 RT Path

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Non-Functional Requirement

Parent Stakeholder Requirement: Traces to: #33 (HAL Interface: PEv2)

Quality Attribute Category: Real-Time (timing constraints, determinism)

Requirement Description

All PEv2 HAL update functions (pev2_read_device_to_hal(), pev2_write_hal_to_device())
shall complete within the LinuxCNC servo thread deadline. No blocking socket calls,
mutex locks, malloc(), or free() shall appear in any code path executed from the
RT servo thread for PEv2 operations.

All PoKeysLib function calls in the RT path shall use the *Async variants exclusively.

Measurable Criteria

Metric	Target	Measurement Method
pev2_read_device_to_hal() worst-case time	< 2 µs	RT trace
pev2_write_hal_to_device() worst-case time	< 2 µs	RT trace
Blocking socket calls in PEv2 RT path	0	Static code inspection
Dynamic memory allocation in PEv2 RT path	0	Static code inspection
Mutex/condition variable usage in PEv2 RT path	0	Static code inspection

Verification Method

Inspection + Analysis

Priority

P0 – Critical

Traceability

• Traces to: HAL Interface: PEv2 #33
• Refined by: (ADR issues — see comment)
• Implemented in: PoKeysLibPulseEngine_v2Async.c (async variants only)
• Verified by: (TEST issues — add when created)