xcb: stablilize xkb state when keymap updated

QXcbKeyboard only deals with core_device_id. With the reporter's test
case: using xdotool to send a string, the deviceID is not changed,
then we assume xkb_state_new() is more stable(or correct) than
xkb_x11_state_new_from_device() in this case.

See also https://www.x.org/releases/current/doc/man/man3/xcb_xkb_new_keyboard_notify_event_t.3.xhtml .

Fixes: QTBUG-95933
Change-Id: Ic595e1f1424fbc6814871a85ac159907f1aeb12a
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Zhang Hao <zhanghao@uniontech.com>
Reviewed-by: Liang Qi <liang.qi@qt.io>
(cherry picked from commit 27c25fc909c19ddc4750f36d26b7c500db9eb0ab)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

3 files changed, 22 insertions, 5 deletions

diff --git a/src/plugins/platforms/xcb/qxcbconnection.cpp b/src/plugins/platforms/xcb/qxcbconnection.cpp
index c667de0f78..8f22a4db13 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.cpp
+++ b/src/plugins/platforms/xcb/qxcbconnection.cpp
@@ -750,7 +750,7 @@ void QXcbConnection::handleXcbEvent(xcb_generic_event_t *event)
                 case XCB_XKB_NEW_KEYBOARD_NOTIFY: {
                     xcb_xkb_new_keyboard_notify_event_t *ev = &xkb_event->new_keyboard_notify;
                     if (ev->changed & XCB_XKB_NKN_DETAIL_KEYCODES)
-                        m_keyboard->updateKeymap();
+                        m_keyboard->updateKeymap(ev);
                     break;
                 }
                 default:
diff --git a/src/plugins/platforms/xcb/qxcbkeyboard.cpp b/src/plugins/platforms/xcb/qxcbkeyboard.cpp
index b2ce353ae9..e0537fc068 100644
--- a/src/plugins/platforms/xcb/qxcbkeyboard.cpp
+++ b/src/plugins/platforms/xcb/qxcbkeyboard.cpp
@@ -365,6 +365,17 @@ void QXcbKeyboard::updateKeymap(xcb_mapping_notify_event_t *event)
     updateKeymap();
 }
 
+void QXcbKeyboard::updateKeymap(xcb_xkb_new_keyboard_notify_event_t *event)
+{
+    if (!event)
+        return;
+
+    if (event->deviceID != event->oldDeviceID)
+        m_config = false;
+
+    updateKeymap();
+}
+
 void QXcbKeyboard::updateKeymap()
 {
     KeysymModifierMap keysymMods;
@@ -372,8 +383,6 @@ void QXcbKeyboard::updateKeymap()
         keysymMods = keysymsToModifiers();
     updateModifiers(keysymMods);
 
-    m_config = true;
-
     if (!m_xkbContext) {
         m_xkbContext.reset(xkb_context_new(XKB_CONTEXT_NO_DEFAULT_INCLUDES));
         if (!m_xkbContext) {
@@ -389,8 +398,13 @@ void QXcbKeyboard::updateKeymap()
     if (connection()->hasXKB()) {
         m_xkbKeymap.reset(xkb_x11_keymap_new_from_device(m_xkbContext.get(), xcb_connection(),
                                                          core_device_id, XKB_KEYMAP_COMPILE_NO_FLAGS));
-        if (m_xkbKeymap)
-            m_xkbState.reset(xkb_x11_state_new_from_device(m_xkbKeymap.get(), xcb_connection(), core_device_id));
+        if (m_xkbKeymap) {
+            if (m_config)
+                m_xkbState.reset(xkb_state_new(m_xkbKeymap.get()));
+            else
+                m_xkbState.reset(xkb_x11_state_new_from_device(m_xkbKeymap.get(), xcb_connection(), core_device_id));
+
+        }
     } else {
         m_xkbKeymap.reset(keymapFromCore(keysymMods));
         if (m_xkbKeymap)
@@ -411,6 +425,8 @@ void QXcbKeyboard::updateKeymap()
     updateXKBMods();
 
     QXkbCommon::verifyHasLatinLayout(m_xkbKeymap.get());
+
+    m_config = true;
 }
 
 QList<int> QXcbKeyboard::possibleKeys(const QKeyEvent *event) const
diff --git a/src/plugins/platforms/xcb/qxcbkeyboard.h b/src/plugins/platforms/xcb/qxcbkeyboard.h
index 1252512e13..470f690d50 100644
--- a/src/plugins/platforms/xcb/qxcbkeyboard.h
+++ b/src/plugins/platforms/xcb/qxcbkeyboard.h
@@ -69,6 +69,7 @@ public:
 
     Qt::KeyboardModifiers translateModifiers(int s) const;
     void updateKeymap(xcb_mapping_notify_event_t *event);
+    void updateKeymap(xcb_xkb_new_keyboard_notify_event_t *event);
     void updateKeymap();
     QList<int> possibleKeys(const QKeyEvent *event) const;