From 21721e967bb9da50623b4889456fff893a5262e5 Mon Sep 17 00:00:00 2001
From: Thomas Schlichter <thomas.schlichter@iis.fraunhofer.de>
Date: Fri, 4 Nov 2022 18:18:35 +0100
Subject: [PATCH 1/2] workaround issue of N310 with UHD >= 4.2.0 when changing
 the BW

UHD issue was reported here:
https://github.com/EttusResearch/uhd/issues/644
---
 radio/USRP/USERSPACE/LIB/usrp_lib.cpp | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/radio/USRP/USERSPACE/LIB/usrp_lib.cpp b/radio/USRP/USERSPACE/LIB/usrp_lib.cpp
index 2a351dcce0..2b38ee4fb1 100644
--- a/radio/USRP/USERSPACE/LIB/usrp_lib.cpp
+++ b/radio/USRP/USERSPACE/LIB/usrp_lib.cpp
@@ -1417,11 +1417,13 @@ extern "C" {
   s->tx_stream = s->usrp->get_tx_stream(stream_args_tx);
 
   /* Setting TX/RX BW after streamers are created due to USRP calibration issue */
-  for(int i=0; i<((int) s->usrp->get_tx_num_channels()) && i<openair0_cfg[0].tx_num_channels; i++)
-    s->usrp->set_tx_bandwidth(openair0_cfg[0].tx_bw,i+choffset);
+  if (device->type != USRP_N300_DEV) { // N310 with UHD >= 4.2.0 has issues with changing the BW
+    for(int i=0; i<((int) s->usrp->get_tx_num_channels()) && i<openair0_cfg[0].tx_num_channels; i++)
+      s->usrp->set_tx_bandwidth(openair0_cfg[0].tx_bw,i+choffset);
 
-  for(int i=0; i<((int) s->usrp->get_rx_num_channels()) && i<openair0_cfg[0].rx_num_channels; i++)
-    s->usrp->set_rx_bandwidth(openair0_cfg[0].rx_bw,i+choffset);
+    for(int i=0; i<((int) s->usrp->get_rx_num_channels()) && i<openair0_cfg[0].rx_num_channels; i++)
+      s->usrp->set_rx_bandwidth(openair0_cfg[0].rx_bw,i+choffset);
+  }
 
   for (int i=0; i<openair0_cfg[0].rx_num_channels; i++) {
     LOG_I(HW,"RX Channel %d\n",i);

From 4591eac55632dd1c7dd8b4e6d9c08a76d3a3c87e Mon Sep 17 00:00:00 2001
From: Robert Schmidt <robert.schmidt@openairinterface.org>
Date: Wed, 16 Nov 2022 09:22:32 +0000
Subject: [PATCH 2/2] extend comment on issue with USRP N310 and UHD >= 4.2.0

---
 radio/USRP/USERSPACE/LIB/usrp_lib.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/radio/USRP/USERSPACE/LIB/usrp_lib.cpp b/radio/USRP/USERSPACE/LIB/usrp_lib.cpp
index 2b38ee4fb1..abbaddb255 100644
--- a/radio/USRP/USERSPACE/LIB/usrp_lib.cpp
+++ b/radio/USRP/USERSPACE/LIB/usrp_lib.cpp
@@ -1417,7 +1417,9 @@ extern "C" {
   s->tx_stream = s->usrp->get_tx_stream(stream_args_tx);
 
   /* Setting TX/RX BW after streamers are created due to USRP calibration issue */
-  if (device->type != USRP_N300_DEV) { // N310 with UHD >= 4.2.0 has issues with changing the BW
+  // N310 with UHD >= 4.2.0 has issues with changing the BW, which is a NOP on N310 in earlier versions
+  // see also: https://github.com/EttusResearch/uhd/issues/644
+  if (device->type != USRP_N300_DEV) {
     for(int i=0; i<((int) s->usrp->get_tx_num_channels()) && i<openair0_cfg[0].tx_num_channels; i++)
       s->usrp->set_tx_bandwidth(openair0_cfg[0].tx_bw,i+choffset);