From 77c578171c9ceb8c4b331bfad1f1bc22e0657e51 Mon Sep 17 00:00:00 2001
From: Rahix <rahix@rahix.de>
Date: Sat, 25 Apr 2026 16:07:45 +0200
Subject: [PATCH 1/2] fdl: active: Fix GAP polling when NS==TS

Ensure the active station does not poll itself when the next_station is
also the active station itself (= it is alone on the bus).

Fixes: 05150b926295 ("fdl: active: Ensure GAP never scans own address")
---
 src/fdl/active.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/fdl/active.rs b/src/fdl/active.rs
index 674b5bc..5eb2434 100644
--- a/src/fdl/active.rs
+++ b/src/fdl/active.rs
@@ -666,6 +666,9 @@ impl FdlActiveStation {
         if next_address >= next_station && next_station > self.p.address {
             // We have reached the end of the GAP, enter waiting state.
             GapState::Waiting { rotation_count: 0 }
+        } else if next_address == next_station && next_station == self.p.address {
+            // We have reached the end of the GAP, enter waiting state (NS==TS case).
+            GapState::Waiting { rotation_count: 0 }
         } else if next_address >= next_station
             && next_station < self.p.address
             && next_address < self.p.address

From dcd13333224014e1ad1fc1fd6eb4bee6497d13ae Mon Sep 17 00:00:00 2001
From: Rahix <rahix@rahix.de>
Date: Sat, 25 Apr 2026 16:10:04 +0200
Subject: [PATCH 2/2] fdl: tests: Add test for single active station GAP
 polling

Catch any self-polling issues when an active station is alone on the bus
and polls the full address space itself.
---
 src/fdl/test_active.rs | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/fdl/test_active.rs b/src/fdl/test_active.rs
index 2102f11..2c16988 100644
--- a/src/fdl/test_active.rs
+++ b/src/fdl/test_active.rs
@@ -535,6 +535,25 @@ fn two_rotations_before_ready() {
     fdl_ut.wait_for_matching(|t| t == fdl::Telegram::Token(fdl::TokenTelegram { da: 15, sa: 7 }));
 }
 
+/// Test that an active station polls all its GAP fine
+#[test]
+fn active_station_full_gap_scanned() {
+    crate::test_utils::prepare_test_logger();
+    let mut fdl_ut = FdlActiveUnderTest::new(7);
+
+    for addr in [8, 3, 6, 8, 11] {
+        fdl_ut.wait_for_matching(|t| {
+            if let fdl::Telegram::Data(data_telegram) = t {
+                data_telegram.is_fdl_status_request().is_some()
+                    && data_telegram.h.da == addr
+                    && data_telegram.h.sa == 7
+            } else {
+                false
+            }
+        });
+    }
+}
+
 /// Test that an active station discovers another active neighbor station.
 #[test]
 fn active_station_discovers_neighbor() {