From 3c5a5728b228de81fda161efefdf4377ba99b57a Mon Sep 17 00:00:00 2001
From: Dominic Clifton <dominic.clifton@cleanflight.com>
Date: Sun, 23 Jan 2022 17:46:23 +0100
Subject: [PATCH] ExpressLRS - Fix an edge-case when a receiver can have both
 of it's ISR flags set.

This has not been observed on the bench but is more of a safeguard so that
the task doesn't stall and can decide what to do.
---
 src/main/drivers/rx/rx_sx127x.c | 4 +++-
 src/main/drivers/rx/rx_sx1280.c | 5 ++++-
 src/main/rx/expresslrs.c        | 4 +++-
 src/main/rx/expresslrs_impl.h   | 3 ++-
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/main/drivers/rx/rx_sx127x.c b/src/main/drivers/rx/rx_sx127x.c
index aa85fd13a..3bc605e38 100644
--- a/src/main/drivers/rx/rx_sx127x.c
+++ b/src/main/drivers/rx/rx_sx127x.c
@@ -445,7 +445,9 @@ uint8_t sx127xGetIrqReason(void)
 {
     uint8_t irqFlags = sx127xGetIrqFlags();
     sx127xClearIrqFlags();
-    if ((irqFlags & SX127X_CLEAR_IRQ_FLAG_TX_DONE)) {
+    if ((irqFlags & SX127X_CLEAR_IRQ_FLAG_TX_DONE) && (irqFlags & SX127X_CLEAR_IRQ_FLAG_RX_DONE)) {
+        return 3;
+    } else if ((irqFlags & SX127X_CLEAR_IRQ_FLAG_TX_DONE)) {
         return 2;
     } else if ((irqFlags & SX127X_CLEAR_IRQ_FLAG_RX_DONE)) {
         return 1;
diff --git a/src/main/drivers/rx/rx_sx1280.c b/src/main/drivers/rx/rx_sx1280.c
index 7d35d88f2..7d4c14186 100644
--- a/src/main/drivers/rx/rx_sx1280.c
+++ b/src/main/drivers/rx/rx_sx1280.c
@@ -418,8 +418,11 @@ void sx1280ClearIrqStatus(const uint16_t irqMask)
 uint8_t sx1280GetIrqReason(void)
 {
     uint16_t irqStatus = sx1280GetIrqStatus();
+
     sx1280ClearIrqStatus(SX1280_IRQ_RADIO_ALL);
-    if ((irqStatus & SX1280_IRQ_TX_DONE)) {
+    if ((irqStatus & SX1280_IRQ_TX_DONE) && (irqStatus & SX1280_IRQ_RX_DONE)) {
+        return 3;
+    } else if ((irqStatus & SX1280_IRQ_TX_DONE)) {
         return 2;
     } else if ((irqStatus & SX1280_IRQ_RX_DONE)) {
         return 1;
diff --git a/src/main/rx/expresslrs.c b/src/main/rx/expresslrs.c
index 4991b06e5..d5d5ddbcc 100644
--- a/src/main/rx/expresslrs.c
+++ b/src/main/rx/expresslrs.c
@@ -1073,7 +1073,9 @@ rx_spi_received_e expressLrsDataReceived(uint8_t *payload)
     }
 
     uint8_t irqReason = receiver.rxISR(&isrTimeStampUs);
-    if (irqReason == ELRS_DIO_TX_DONE) {
+    if (irqReason == ELRS_DIO_RX_AND_TX_DONE) {
+        startReceiving();
+    } else if (irqReason == ELRS_DIO_TX_DONE) {
         startReceiving();
     } else if (irqReason == ELRS_DIO_RX_DONE) {
         result = processRFPacket(payload, isrTimeStampUs);
diff --git a/src/main/rx/expresslrs_impl.h b/src/main/rx/expresslrs_impl.h
index 2655cf2c9..fdc6d8548 100644
--- a/src/main/rx/expresslrs_impl.h
+++ b/src/main/rx/expresslrs_impl.h
@@ -33,7 +33,8 @@ typedef enum {
 typedef enum {
     ELRS_DIO_UNKNOWN = 0,
     ELRS_DIO_RX_DONE = 1,
-    ELRS_DIO_TX_DONE = 2
+    ELRS_DIO_TX_DONE = 2,
+    ELRS_DIO_RX_AND_TX_DONE = 3,
 } dioReason_e;
 
 typedef enum {