Mixed FS+Wiitek test pair: modules dispatched by EEPROM PN to a BCM or Go RollBall client (whitelist panics outside the wiitek proven-safe set), SNR now solely the wiitek's IEEE margins (BCM handler SNR dropped as unactionable), ECD-clears-AN-enable trap found and fixed (7.0 |= 0x1200 on every restart, explicit restart after each diag), mixed roles FS-slave/wiitek-auto-master, window re-arms at taken edge so the one CMD write per window sits far from the poll; X710 rejects the honest FS EEPROM so the noise pair runs Fibergaga+Wiitek

docs/modules/README.md

@@ -26,6 +26,7 @@ Counts and current placement: [../state.md](../state.md).
 | 10Gtek | `SFP-10G-SR` part number | (not in the test set) |
 
 - `allow_unsupported_sfp=1` is mandatory on the X520 — and it's the *truthful* module that requires it ([../nics/x520/](../nics/x520/README.md)).
+- The X710 rejects the FS outright: i40e firmware disables Rx/Tx ("unsupported SFP module type", logged only at driver bind) and i40e has no override parameter — the FS can only live behind ixgbe. The rejection is silent at insertion time; a dead port with `ethtool` reporting no supported link modes is the symptom.
 - Physical-layer reasoning must use 10GBASE-T: PAM16, LDPC FEC, self-synchronizing scrambler, 4 twisted pairs, distance/temperature sensitive — never an optical model.
 - The module PHYs keep the copper link trained on their own: an admin `ip link set down` does NOT drop the wire unless the i40e `link-down-on-close` priv flag is set (peer sees the drop in ~200 ms, relinks in ~0.9 s).
 
@@ -39,7 +40,7 @@ Proven on the CUX3610 (before the originals died) and the Fibergaga; the BCM not
 | PCS 3.32/3.33 | Block-lock loss, BER saturate, errored blocks | Latched, clear-on-read |
 | AN 7.33 | Link-partner status / master-slave | |
 | PMA 1.147 | Fast retrain status/count | Per-run quality metric |
-| AN 7.0 bit 9 | Restart AN — forces retrain, refreshes SNR minimums | Proven safe everywhere. An `ip link` bounce does not drop the copper line, so it won't retrain |
+| AN 7.0 | Restart AN (`\|= 0x1200`, enable + restart) — forces retrain, refreshes SNR minimums | Proven safe everywhere. Always force the enable bit too: the BCM ECD can leave 7.0.12 cleared ([fs/](fs/README.md)), and a bare restart preserves it. An `ip link` bounce does not drop the copper line, so it won't retrain |
 
 ## RollBall protocol (Marvell and Aquantia modules)
 
@@ -49,7 +50,7 @@ Clause-45 access to the internal PHY over I2C A2h, all messages ≤ 4 B, offset-
 2. Page-select: A2h 0x7F → 3.
 3. Mailbox: A2h 0x80 (cmd) / 0x81 (data), poll for DONE (0x04).
 
-Split transactions (separate STOP per byte) are field-proven on both the Fibergaga and the original Wiiteks; the kernel `mdio-i2c` combined form is not required by the modules.
+The full mailbox map (0x80 CMD, 0x81 devad, 0x82/0x83 reg, 0x84/0x85 value) is vendor-confirmed in [wiitek/10gbase-t-phy-register-operation.md](wiitek/10gbase-t-phy-register-operation.md). Split transactions (separate STOP per byte) are field-proven on both the Fibergaga and the original Wiiteks; the kernel `mdio-i2c` combined form is not required by the modules. cabletest carries a Go client (`phy.go`): split ≤4-byte offset writes, single-hold compound reads, whitelist-guarded against the Wiitek brick space — proven live over the patched-ixgbe `sff_i2c` on the X520.
 
 ## Cable-length physics (applies to all vendors)