From 3bb4f48faf2aa1a80e4e96c4cdc5d05de942ffe2 Mon Sep 17 00:00:00 2001
From: Jakob Ketterl <jakob.ketterl@gmx.de>
Date: Thu, 26 Aug 2021 17:22:10 +0200
Subject: [PATCH] fix errors on shutdown (duplicate calls)

---
 owrx/fft.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/owrx/fft.py b/owrx/fft.py
index e97c5a8..e1a8004 100644
--- a/owrx/fft.py
+++ b/owrx/fft.py
@@ -84,7 +84,11 @@ class SpectrumThread(SdrSourceEventClient):
                 self.dsp.setReader(self.sdrSource.getBuffer().getReader())
 
     def onFail(self):
+        if self.dsp is None:
+            return
         self.dsp.stop()
 
     def onShutdown(self):
+        if self.dsp is None:
+            return
         self.dsp.stop()