Unplugged-cable behavior fixed end to end: heat grid rolls on the slot boundary (view computes the newest slot from the draw clock; history sampled every frame so slots color within a frame; noise phase displayed as commanded straight from the shared clock — radiating and the per-slot vote deleted), SNR ghost panic disambiguated via the PMA 1.1 latch (link dropped mid-read discards the batch, ghost on a proven-up link still dies), measure skips the 25s relink wait when the ECD verdict says faulted and the header says MEASURING instead of GOOD while a diag runs, RollBall mailbox deadline resized to 10s from bench measurement (<25ms linked, ~220ms no-link, >3s during a live plug's training; docs/modules/wiitek updated)

rollball.go

@@ -25,8 +25,10 @@ const (
 
 	rbReadDelayUs = 500
 	rbCmdPoll     = 20 * time.Millisecond
-	// Matches the BCM allowance for a handler frozen by 10GBASE-T training.
-	rbCmdTimeout = 3 * time.Second
+	// Bench-measured: <25 ms linked, ~220 ms steady with no link, and >3 s
+	// while a live plug event's training ran — sized past a full ~6 s
+	// training, so a cable plugged mid-read reads busy, not dead.
+	rbCmdTimeout = 10 * time.Second
 
 	rbPHYIDHi uint16 = 0x002B
 	rbPHYIDLo uint16 = 0x0BF4
@@ -168,7 +170,12 @@ func (r *rollball) identify() (ident string, err error) {
 	return
 }
 
-func (r *rollball) snrMargins() (out [4]float64, err error) {
+// An untrained PHY honestly serves 0x0000 here, so an out-of-band value is
+// only a ghost if the link stayed up across the reads. The caller drained the
+// PMA 1.1 latch when it checked the link, so one latched read now answers
+// that: a drop since means the unplug race — discard the batch, ok false, and
+// the next poll reads the link down.
+func (r *rollball) snrMargins() (out [4]float64, ok bool, err error) {
 	r.exec(func() {
 		for i := range out {
 			var v uint16
@@ -177,10 +184,19 @@ func (r *rollball) snrMargins() (out [4]float64, err error) {
 			}
 			m := (float64(v) - 0x8000) / 10
 			if m < rbGhostLow || m > rbGhostHigh {
-				panic(fmt.Sprintf("%s: ghost SNR margin %.1f dB (1.%d=%#04x)", r.ifname, m, 133+i, v))
+				var link uint16
+				if link, err = r.mdioRead(1, 1); err != nil {
+					return
+				}
+				if link&0x0004 == 0 {
+					return
+				}
+				panic(fmt.Sprintf("%s: ghost SNR margin %.1f dB (1.%d=%#04x) with the link up",
+					r.ifname, m, 133+i, v))
 			}
 			out[i] = m
 		}
+		ok = true
 	})
 	return
 }