Support LEDs in Xkb and libinput

Summary:
The Xkb implementation starts to track the state of the LEDs in the
keymap and emits a signal whenever the LEDs change. This signal is
connected to a method in LibInput::Connection which updates the led
state on all devices and uses it to init the state of the led when a new
device gets connected.

BUG: 369214
FIXED-IN: 5.8.2

Test Plan: Connected a keyboard with LEDs and enabled NumLock and ScrollLock.

Reviewers: #kwin, #plasma_on_wayland

Subscribers: plasma-devel, kwin

Tags: #plasma_on_wayland, #kwin

Differential Revision: https://phabricator.kde.org/D2943

input.cpp

@@ -1233,7 +1233,9 @@ void InputRedirection::setupLibInput()
     m_libInput = conn;
     if (conn) {
         conn->setInputConfig(m_inputConfig);
+        conn->updateLEDs(m_keyboard->xkb()->leds());
         conn->setup();
+        connect(m_keyboard, &KeyboardInputRedirection::ledsChanged, conn, &LibInput::Connection::updateLEDs);
         connect(conn, &LibInput::Connection::eventsRead, this,
             [this] {
                 m_libInput->processEvents();

keyboard_input.cpp

@@ -90,10 +90,15 @@ Xkb::Xkb(InputRedirection *input)
     , m_controlModifier(0)
     , m_altModifier(0)
     , m_metaModifier(0)
+    , m_numLock(0)
+    , m_capsLock(0)
+    , m_scrollLock(0)
     , m_modifiers(Qt::NoModifier)
     , m_consumedModifiers(Qt::NoModifier)
     , m_keysym(XKB_KEY_NoSymbol)
+    , m_leds()
 {
+    qRegisterMetaType<KWin::Xkb::LEDs>();
     if (!m_context) {
         qCDebug(KWIN_XKB) << "Could not create xkb context";
     } else {
@@ -219,6 +224,11 @@ void Xkb::updateKeymap(xkb_keymap *keymap)
     m_controlModifier = xkb_keymap_mod_get_index(m_keymap, XKB_MOD_NAME_CTRL);
     m_altModifier     = xkb_keymap_mod_get_index(m_keymap, XKB_MOD_NAME_ALT);
     m_metaModifier    = xkb_keymap_mod_get_index(m_keymap, XKB_MOD_NAME_LOGO);
+
+    m_numLock         = xkb_keymap_led_get_index(m_keymap, XKB_LED_NAME_NUM);
+    m_capsLock        = xkb_keymap_led_get_index(m_keymap, XKB_LED_NAME_CAPS);
+    m_scrollLock      = xkb_keymap_led_get_index(m_keymap, XKB_LED_NAME_SCROLL);
+
     m_currentLayout = xkb_state_serialize_layout(m_state, XKB_STATE_LAYOUT_EFFECTIVE);
 
     createKeymapFile();
@@ -346,6 +356,23 @@ void Xkb::updateModifiers()
         mods |= Qt::MetaModifier;
     }
     m_modifiers = mods;
+
+    // update LEDs
+    LEDs leds;
+    if (xkb_state_led_index_is_active(m_state, m_numLock) == 1) {
+        leds = leds | LED::NumLock;
+    }
+    if (xkb_state_led_index_is_active(m_state, m_capsLock) == 1) {
+        leds = leds | LED::CapsLock;
+    }
+    if (xkb_state_led_index_is_active(m_state, m_scrollLock) == 1) {
+        leds = leds | LED::ScrollLock;
+    }
+    if (m_leds != leds) {
+        m_leds = leds;
+        emit m_input->keyboard()->ledsChanged(m_leds);
+    }
+
     const xkb_layout_index_t layout = xkb_state_serialize_layout(m_state, XKB_STATE_LAYOUT_EFFECTIVE);
     if (layout != m_currentLayout) {
         m_currentLayout = layout;

keyboard_input.h

@@ -36,6 +36,7 @@ struct xkb_state;
 struct xkb_compose_table;
 struct xkb_compose_state;
 typedef uint32_t xkb_mod_index_t;
+typedef uint32_t xkb_led_index_t;
 typedef uint32_t xkb_keysym_t;
 
 namespace KWin
@@ -71,6 +72,16 @@ public:
 
     void switchToNextLayout();
 
+    enum class LED {
+        NumLock = 1 << 0,
+        CapsLock = 1 << 1,
+        ScrollLock = 1 << 2
+    };
+    Q_DECLARE_FLAGS(LEDs, LED)
+    LEDs leds() const {
+        return m_leds;
+    }
+
 private:
     xkb_keymap *loadKeymapFromConfig();
     xkb_keymap *loadDefaultKeymap();
@@ -87,6 +98,9 @@ private:
     xkb_mod_index_t m_controlModifier;
     xkb_mod_index_t m_altModifier;
     xkb_mod_index_t m_metaModifier;
+    xkb_led_index_t m_numLock;
+    xkb_led_index_t m_capsLock;
+    xkb_led_index_t m_scrollLock;
     Qt::KeyboardModifiers m_modifiers;
     Qt::KeyboardModifiers m_consumedModifiers;
     xkb_keysym_t m_keysym;
@@ -100,6 +114,7 @@ private:
         xkb_compose_table *table = nullptr;
         xkb_compose_state *state = nullptr;
     } m_compose;
+    LEDs m_leds;
 };
 
 class KeyboardInputRedirection : public QObject
@@ -133,6 +148,9 @@ public:
         return m_xkb->modifiers();
     }
 
+Q_SIGNALS:
+    void ledsChanged(KWin::Xkb::LEDs);
+
 private Q_SLOTS:
     void reconfigure();
 
@@ -156,4 +174,7 @@ Qt::KeyboardModifiers Xkb::modifiers() const
 
 }
 
+Q_DECLARE_METATYPE(KWin::Xkb::LED)
+Q_DECLARE_METATYPE(KWin::Xkb::LEDs)
+
 #endif

libinput/connection.cpp

@@ -47,6 +47,21 @@ QThread *Connection::s_thread = nullptr;
 
 static Context *s_context = nullptr;
 
+static quint32 toLibinputLEDS(Xkb::LEDs leds)
+{
+    quint32 libinputLeds = 0;
+    if (leds.testFlag(Xkb::LED::NumLock)) {
+        libinputLeds = libinputLeds | LIBINPUT_LED_NUM_LOCK;
+    }
+    if (leds.testFlag(Xkb::LED::CapsLock)) {
+        libinputLeds = libinputLeds | LIBINPUT_LED_CAPS_LOCK;
+    }
+    if (leds.testFlag(Xkb::LED::ScrollLock)) {
+        libinputLeds = libinputLeds | LIBINPUT_LED_SCROLL_LOCK;
+    }
+    return libinputLeds;
+}
+
 Connection::Connection(QObject *parent)
     : Connection(nullptr, parent)
 {
@@ -95,6 +110,7 @@ Connection::Connection(Context *input, QObject *parent)
     , m_input(input)
     , m_notifier(nullptr)
     , m_mutex(QMutex::Recursive)
+    , m_leds()
 {
     Q_ASSERT(m_input);
 
@@ -246,6 +262,10 @@ void Connection::processEvents()
                     }
                 }
                 applyDeviceConfig(device);
+
+                // enable possible leds
+                libinput_device_led_update(device->device(), static_cast<libinput_led>(toLibinputLEDS(m_leds)));
+
                 emit deviceAdded(device);
                 break;
             }
@@ -513,5 +533,18 @@ void Connection::toggleTouchpads()
     }
 }
 
+void Connection::updateLEDs(Xkb::LEDs leds)
+{
+    if (m_leds == leds) {
+        return;
+    }
+    m_leds = leds;
+    // update on devices
+    const libinput_led l = static_cast<libinput_led>(toLibinputLEDS(leds));
+    for (auto it = m_devices.constBegin(), end = m_devices.constEnd(); it != end; ++it) {
+        libinput_device_led_update((*it)->device(), l);
+    }
+}
+
 }
 }

libinput/connection.h

@@ -21,6 +21,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define KWIN_LIBINPUT_CONNECTION_H
 
 #include "../input.h"
+#include "../keyboard_input.h"
 #include <kwinglobals.h>
 
 #include <QObject>
@@ -82,6 +83,8 @@ public:
         return m_devices;
     }
 
+    void updateLEDs(KWin::Xkb::LEDs leds);
+
 Q_SIGNALS:
     void keyChanged(quint32 key, KWin::InputRedirection::KeyboardKeyState, quint32 time, KWin::LibInput::Device *device);
     void pointerButtonChanged(quint32 button, KWin::InputRedirection::PointerButtonState state, quint32 time, KWin::LibInput::Device *device);
@@ -135,6 +138,7 @@ private:
     QVector<Device*> m_devices;
     KSharedConfigPtr m_config;
     bool m_touchpadsEnabled = true;
+    Xkb::LEDs m_leds;
 
     KWIN_SINGLETON(Connection)
     static QThread *s_thread;