Clarify ResetNotification in QSurfaceFormat a bit

Add some more details to make it a bit easier for advanced users
to grasp what this is about.

Task-number: QTBUG-80257
Pick-to: 5.15
Change-Id: I9969b5b62384a25d5e90b57ef25c83a8a2a6c9c7
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

src/gui/kernel/qopenglcontext.cpp

@@ -524,6 +524,14 @@ QOpenGLContext::~QOpenGLContext()
     OpenGL context by calling create(), call makeCurrent() again and then
     reinitialize all OpenGL resources.
 
+    On some platforms context loss situations is not something that can
+    avoided. On others however, they may need to be opted-in to. This can be
+    done by enabling \l{QSurfaceFormat::ResetNotification}{ResetNotification} in
+    the QSurfaceFormat. This will lead to setting
+    \c{RESET_NOTIFICATION_STRATEGY_EXT} to \c{LOSE_CONTEXT_ON_RESET_EXT} in the
+    underlying native OpenGL context. QOpenGLContext will then monitor the
+    status via \c{glGetGraphicsResetStatusEXT()} in every makeCurrent().
+
     \sa create()
 */
 bool QOpenGLContext::isValid() const

src/gui/kernel/qsurfaceformat.cpp

@@ -148,7 +148,10 @@ public:
     \value ResetNotification Enables notifications about resets of the OpenGL context. The status is then
         queryable via the context's \l{QOpenGLContext::isValid()}{isValid()} function. Note that not setting
         this flag does not guarantee that context state loss never occurs. Additionally, some implementations
-        may choose to report context loss regardless of this flag.
+        may choose to report context loss regardless of this flag. Platforms that support dynamically enabling
+        the monitoring of the loss of context, such as, Windows with WGL, or Linux/X11 (xcb) with GLX, will
+        monitor the status in every call to \l{QOpenGLContext::makeCurrent()}{makeCurrent()}. See
+        \l{QOpenGLContext::isValid()}{isValid()} for more information on this.
 */
 
 /*!