From b85c24a79c7a478830aad4933bb29fbf413d9609 Mon Sep 17 00:00:00 2001
From: Kevin-OConnor <koconnor@usfirst.org>
Date: Thu, 30 Dec 2021 16:13:03 -0500
Subject: [PATCH] [wpilib] Add warning about onboard I2C (#3842)

---
 wpilibc/src/main/native/cpp/I2C.cpp                  | 8 ++++++++
 wpilibj/src/main/java/edu/wpi/first/wpilibj/I2C.java | 6 ++++++
 2 files changed, 14 insertions(+)

diff --git a/wpilibc/src/main/native/cpp/I2C.cpp b/wpilibc/src/main/native/cpp/I2C.cpp
index adf1c54860..dcfb2b8f4d 100644
--- a/wpilibc/src/main/native/cpp/I2C.cpp
+++ b/wpilibc/src/main/native/cpp/I2C.cpp
@@ -16,6 +16,14 @@ using namespace frc;
 I2C::I2C(Port port, int deviceAddress)
     : m_port(static_cast<HAL_I2CPort>(port)), m_deviceAddress(deviceAddress) {
   int32_t status = 0;
+
+  if (port == I2C::Port::kOnboard) {
+    FRC_ReportError(warn::Warning, "{}",
+                    "Onboard I2C port is subject to system lockups. See Known "
+                    "Issues page for "
+                    "details");
+  }
+
   HAL_InitializeI2C(m_port, &status);
   FRC_CheckErrorStatus(status, "Port {}", port);
 
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/I2C.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/I2C.java
index 1d148a7689..03a00cc3a2 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/I2C.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/I2C.java
@@ -43,6 +43,12 @@ public class I2C implements AutoCloseable {
     m_port = port.value;
     m_deviceAddress = deviceAddress;
 
+    if (port == I2C.Port.kOnboard) {
+      DriverStation.reportWarning(
+          "Onboard I2C port is subject to system lockups. See Known Issues page for details",
+          false);
+    }
+
     I2CJNI.i2CInitialize((byte) port.value);
 
     HAL.report(tResourceType.kResourceType_I2C, deviceAddress);