From dd3401fd90f532095e8bf7744627b966a47baeaa Mon Sep 17 00:00:00 2001
From: Andrew Onyshchuk <andryk.rv@gmail.com>
Date: Tue, 6 Aug 2024 12:51:04 -0700
Subject: [PATCH] Fix gain mode (rtlsdr)

---
 src/convenience/convenience.c | 25 +++++++++++++------------
 src/rtl_fm.c                  |  7 -------
 2 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/src/convenience/convenience.c b/src/convenience/convenience.c
index d1a33c0..83d470f 100644
--- a/src/convenience/convenience.c
+++ b/src/convenience/convenience.c
@@ -239,14 +239,15 @@ int verbose_auto_gain(SoapySDRDevice *dev, size_t channel)
 {
 	int r;
 	r = 0;
-	/* TODO: not bridged, https://github.com/pothosware/SoapyRTLSDR/search?utf8=✓&q=rtlsdr_set_tuner_gain_mode
-	r = rtlsdr_set_tuner_gain_mode(dev, 0);
-	if (r != 0) {
-		fprintf(stderr, "WARNING: Failed to set tuner gain.\n");
-	} else {
+	if (SoapySDRDevice_hasGainMode(dev, SOAPY_SDR_RX, channel)) {
+		r = SoapySDRDevice_setGainMode(dev, SOAPY_SDR_RX, channel, /*automatic*/ true);
+		if (r != 0) {
+			fprintf(stderr, "WARNING: Failed to enable auto gain: %s\n", SoapySDRDevice_lastError());
+			return r;
+		}
 		fprintf(stderr, "Tuner gain set to automatic.\n");
+		return 0;
 	}
-	*/
 
 	// Per-driver hacks TODO: clean this up
 	char *driver = SoapySDRDevice_getDriverKey(dev);
@@ -288,13 +289,13 @@ int verbose_gain_str_set(SoapySDRDevice *dev, char *gain_str, size_t channel)
 {
 	int r = 0;
 
-	/* TODO: manual gain mode
-	r = rtlsdr_set_tuner_gain_mode(dev, 1);
-	if (r < 0) {
-		fprintf(stderr, "WARNING: Failed to enable manual gain.\n");
-		return r;
+	if (SoapySDRDevice_hasGainMode(dev, SOAPY_SDR_RX, channel)) {
+		r = SoapySDRDevice_setGainMode(dev, SOAPY_SDR_RX, channel, /*automatic*/ false);
+		if (r != 0) {
+			fprintf(stderr, "WARNING: Failed to enable manual gain: %s\n", SoapySDRDevice_lastError());
+			return r;
+		}
 	}
-	*/
 
 	if (strchr(gain_str, '=')) {
 		// Set each gain individually (more control)
diff --git a/src/rtl_fm.c b/src/rtl_fm.c
index 0093007..851c69e 100644
--- a/src/rtl_fm.c
+++ b/src/rtl_fm.c
@@ -225,8 +225,6 @@ void usage(void)
 		"\t	rdc:    enable dc blocking filter on raw I/Q data at capture rate\n"
 		"\t	adc:    enable dc blocking filter on demodulated audio\n"
 		"\t	dc:     same as adc\n"
-		"\t	rtlagc: enable rtl2832's digital agc (default: off)\n"
-		"\t	agc:    same as rtlagc\n"
 		"\t	deemp:  enable de-emphasis filter\n"
 		"\t	direct: enable direct sampling (bypasses tuner, uses rtl2832 xtal)\n"
 		"\t	no-mod: enable no-mod direct sampling\n"
@@ -1213,7 +1211,6 @@ int main(int argc, char **argv)
 	int custom_ppm = 0;
 	int r, opt;
 	int timeConstant = 75; /* default: U.S. 75 uS */
-	int rtlagc = 0;
 	char *antenna_str = NULL;
 	dongle_init(&dongle);
 	demod_init(&demod);
@@ -1292,8 +1289,6 @@ int main(int argc, char **argv)
 				dongle.direct_sampling = 3;}
 			if (strcmp("offset",  optarg) == 0) {
 				dongle.offset_tuning = 1;}
-			if (strcmp("rtlagc", optarg) == 0 || strcmp("agc", optarg) == 0) {
-				rtlagc = 1;}
 			if (strcmp("zero", optarg) == 0) {
 				demod.squelch_zero = 1;}
 			if (strcmp("wav",  optarg) == 0) {
@@ -1429,8 +1424,6 @@ int main(int argc, char **argv)
 		verbose_gain_str_set(dongle.dev, dongle.gain_str, dongle.channel);
 	}
 
-	SoapySDRDevice_setGainMode(dongle.dev, SOAPY_SDR_RX, dongle.channel, rtlagc);
-
 	if (custom_ppm) verbose_ppm_set(dongle.dev, dongle.ppm_error, dongle.channel);
 
  	verbose_set_bandwidth(dongle.dev, dongle.bandwidth, dongle.channel);