From 956f06e612ee8d87482a0c88059f92c8c9144cf1 Mon Sep 17 00:00:00 2001
From: Jan Svabenik <jan@svabi.ch>
Date: Tue, 17 Mar 2026 19:51:50 +0100
Subject: [PATCH] Auto-restart on IQ timeout and report last-sample age

---
 cmd/sdrd/main.go            | 36 ++++++++++++++++++++++++++++++++++++
 internal/sdr/source.go      |  7 ++++---
 internal/sdrplay/sdrplay.go |  8 +++++++-
 web/app.js                  |  3 ++-
 4 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/cmd/sdrd/main.go b/cmd/sdrd/main.go
index e8b4a18..4386e04 100644
--- a/cmd/sdrd/main.go
+++ b/cmd/sdrd/main.go
@@ -10,6 +10,7 @@ import (
 	"os/signal"
 	"path/filepath"
 	"strconv"
+	"strings"
 	"sync"
 	"syscall"
 	"time"
@@ -97,6 +98,36 @@ type sourceManager struct {
 	newSource func(cfg config.Config) (sdr.Source, error)
 }
 
+func (m *sourceManager) Restart(cfg config.Config) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	old := m.src
+	_ = old.Stop()
+	next, err := m.newSource(cfg)
+	if err != nil {
+		_ = old.Start()
+		m.src = old
+		return err
+	}
+	if err := next.Start(); err != nil {
+		_ = next.Stop()
+		_ = old.Start()
+		m.src = old
+		return err
+	}
+	m.src = next
+	return nil
+}
+
+func (m *sourceManager) Stats() sdr.SourceStats {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	if sp, ok := m.src.(sdr.StatsProvider); ok {
+		return sp.Stats()
+	}
+	return sdr.SourceStats{}
+}
+
 func newSourceManager(src sdr.Source, newSource func(cfg config.Config) (sdr.Source, error)) *sourceManager {
 	return &sourceManager{src: src, newSource: newSource}
 }
@@ -463,6 +494,11 @@ func runDSP(ctx context.Context, src sdr.Source, cfg config.Config, det *detecto
 			iq, err := src.ReadIQ(cfg.FFTSize)
 			if err != nil {
 				log.Printf("read IQ: %v", err)
+				if strings.Contains(err.Error(), "timeout") {
+					if err := src.Restart(cfg); err != nil {
+						log.Printf("restart failed: %v", err)
+					}
+				}
 				continue
 			}
 			if !gotSamples {
diff --git a/internal/sdr/source.go b/internal/sdr/source.go
index 9ed74d8..25043e8 100644
--- a/internal/sdr/source.go
+++ b/internal/sdr/source.go
@@ -13,9 +13,10 @@ type ConfigurableSource interface {
 }
 
 type SourceStats struct {
-	BufferSamples int    `json:"buffer_samples"`
-	Dropped       uint64 `json:"dropped"`
-	Resets        uint64 `json:"resets"`
+	BufferSamples   int    `json:"buffer_samples"`
+	Dropped         uint64 `json:"dropped"`
+	Resets          uint64 `json:"resets"`
+	LastSampleAgoMs int64  `json:"last_sample_ago_ms"`
 }
 
 type StatsProvider interface {
diff --git a/internal/sdrplay/sdrplay.go b/internal/sdrplay/sdrplay.go
index 72d37a8..9ea439f 100644
--- a/internal/sdrplay/sdrplay.go
+++ b/internal/sdrplay/sdrplay.go
@@ -97,6 +97,7 @@ type Source struct {
 	bwKHz      int
 	dropped    uint64
 	resets     uint64
+	lastSample time.Time
 	cond       *sync.Cond
 }
 
@@ -284,7 +285,11 @@ func (s *Source) appendRing(samples []complex64) {
 func (s *Source) Stats() sdr.SourceStats {
 	s.mu.Lock()
 	defer s.mu.Unlock()
-	return sdr.SourceStats{BufferSamples: s.size, Dropped: s.dropped, Resets: s.resets}
+	ago := int64(-1)
+	if !s.lastSample.IsZero() {
+		ago = time.Since(s.lastSample).Milliseconds()
+	}
+	return sdr.SourceStats{BufferSamples: s.size, Dropped: s.dropped, Resets: s.resets, LastSampleAgoMs: ago}
 }
 
 func (s *Source) Flush() {
@@ -383,6 +388,7 @@ func goStreamCallback(xi *C.short, xq *C.short, numSamples C.uint, reset C.uint,
 		iq[i] = complex(re, im)
 	}
 	src.mu.Lock()
+	src.lastSample = time.Now()
 	src.appendRing(iq)
 	src.mu.Unlock()
 }
diff --git a/web/app.js b/web/app.js
index 242c9b0..a40136a 100644
--- a/web/app.js
+++ b/web/app.js
@@ -353,7 +353,8 @@ function renderSpectrum() {
 
   const binHz = sample_rate / n;
   const gpuState = gpuInfo.active ? 'GPU:ON' : (gpuInfo.available ? 'GPU:OFF' : 'GPU:N/A');
-  metaEl.textContent = `Center ${(center_hz/1e6).toFixed(3)} MHz | Span ${(span/1e6).toFixed(3)} MHz | Res ${binHz.toFixed(1)} Hz/bin | Buf ${stats.buffer_samples} Drop ${stats.dropped} Reset ${stats.resets} | ${gpuState}`;
+  const lastAge = stats.last_sample_ago_ms >= 0 ? `${stats.last_sample_ago_ms}ms` : 'n/a';
+  metaEl.textContent = `Center ${(center_hz/1e6).toFixed(3)} MHz | Span ${(span/1e6).toFixed(3)} MHz | Res ${binHz.toFixed(1)} Hz/bin | Buf ${stats.buffer_samples} Drop ${stats.dropped} Reset ${stats.resets} Last ${lastAge} | ${gpuState}`;
 }
 
 function renderWaterfall() {