RFE/Bug: WinOF-2 mlx5 delay_drop lacks Linux-equivalent dropless_rq auto rearm for DPDK Rx no-drop use case

Infrastructure & Networking Software And Drivers WinOF Driver
1

Product: NVIDIA/Mellanox ConnectX-5, WinOF-2, DPDK mlx5 PMD on Windows
Request type: RFE / driver feature parity with Linux MLNX_OFED dropless_rq

We need WinOF-2 to support Linux-equivalent dropless_rq auto rearm for Rx delay_drop.

Use case:

  • ConnectX-5 receives 100Gbps UDP traffic from FPGA.
  • FPGA supports PFC priority 0 perfectly.
  • On Linux, DPDK mlx5 delay_drop + kernel dropless_rq on works: when RQ has no WQE, PFC pauses the FPGA and Linux mlx5 driver rearms delay_drop after timeout.
  • On Windows, DPDK can enable RQ delay_drop_en, but after delay_drop timeout WinOF-2 disables the feature and there appears to be no automatic rearm equivalent to Linux dropless_rq.

Observed:

  • Firmware capability reports rq_delay_drop=1 and general_notification_event=1.
  • Windows event log shows dropless/delay-drop timeout events.
  • WinOF-2 DevX SDK exposes event queue APIs, but public API does not appear to expose a usable subscription for MLX5_EVENT_TYPE_GENERAL_EVENT / MLX5_GENERAL_SUBTYPE_DELAY_DROP_TIMEOUT.
  • DPDK Windows mlx5 PMD currently cannot query dropless_rq and cannot perform event-driven rearm.

Request:
Please add a WinOF-2 miniport feature equivalent to Linux dropless_rq:
on MLX5_EVENT_TYPE_GENERAL_EVENT with subtype MLX5_GENERAL_SUBTYPE_DELAY_DROP_TIMEOUT,
issue MLX5_CMD_OP_SET_DELAY_DROP_PARAMS immediately to rearm delay_drop.

Please expose:

  1. A registry/PowerShell/Mlx5Cmd switch to enable/disable auto rearm.
  2. Counters for delay_drop timeout events and successful/failed rearms.
  3. Documentation for DPDK/DevX users.
  4. If driver-side auto rearm is not planned, please provide a supported DevX or OID interface for user-mode/kernel-mode applications to subscribe to the delay-drop timeout event and rearm safely.