Merge remote-tracking branch 'origin/tqtc/lts-5.15.11' into tqtc/lts-5.15-opensourcev5.15.11-lts-lgpl

Change-Id: I43c944790c691789c96a1e9f3b2a118a0589744e

1 files changed, 7 insertions, 0 deletions

diff --git a/src/serialbus/qmodbusdevice.cpp b/src/serialbus/qmodbusdevice.cpp
index ab8e126..58bdc6d 100644
--- a/src/serialbus/qmodbusdevice.cpp
+++ b/src/serialbus/qmodbusdevice.cpp
@@ -204,6 +204,13 @@ void QModbusDevice::setConnectionParameter(int parameter, const QVariant &value)
     \value ReplyAbortedError    The reply was aborted due to a disconnection of
                                 the device.
     \value UnknownError         An unknown error occurred.
+
+    \note An UnknownError can also indicate that the received
+    \l {QModbusPdu::}{FunctionCode} is not supported in the current
+    implementation. In this case custom Modbus client implementations need to
+    override the \l {QModbusClient::}{processResponse()} and
+    \l {QModbusClient::}{processPrivateResponse()} methods to provide support
+    for needed functions.
 */
 
 /*!