From f599f1bd8e2d163b467ae0a44f5c4fcd40aa4969 Mon Sep 17 00:00:00 2001
From: Matthias Wirth <matthias.wirth@gmail.com>
Date: Sat, 27 Apr 2024 15:18:12 +0200
Subject: [PATCH] add option to disable librtlsdr zero copy workaround

only disable workaround if zerocopy is disabled in librtlsdr
otherwise expect significantly increased CPU use
---
 Makefile     | 5 +++++
 sdr_rtlsdr.c | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 884aa362..9b431768 100644
--- a/Makefile
+++ b/Makefile
@@ -38,6 +38,11 @@ else
   LIBS += -lncurses
 endif
 
+# only disable workaround if zerocopy is disabled in librtlsdr, otherwise expect significantly increased CPU use
+ifeq ($(DISABLE_RTLSDR_ZEROCOPY_WORKAROUND), yes)
+  CFLAGS += -DDISABLE_RTLSDR_ZEROCOPY_WORKAROUND
+endif
+
 ifeq ($(HISTORY), yes)
   CFLAGS += -DALL_JSON=1
 endif
diff --git a/sdr_rtlsdr.c b/sdr_rtlsdr.c
index 11018de7..46eefbc0 100644
--- a/sdr_rtlsdr.c
+++ b/sdr_rtlsdr.c
@@ -57,7 +57,7 @@
 
 #include <rtl-sdr.h>
 
-#if defined(__arm__) || defined(__aarch64__)
+#if (defined(__arm__) || defined(__aarch64__)) && !defined(DISABLE_RTLSDR_ZEROCOPY_WORKAROUND)
 // Assume we need to use a bounce buffer to avoid performance problems on Pis running kernel 5.x and using zerocopy
 #  define USE_BOUNCE_BUFFER
 #endif