Fix clazy warning

Modules/devinfo/devicelisting.cpp

@@ -183,7 +183,7 @@ void DeviceListing::deviceAddedSlot(const QString &udi)
   delete solhelp;
 }
 
-void DeviceListing::deviceRemovedSlot(const QString udi) 
+void DeviceListing::deviceRemovedSlot(const QString &udi)
 {
   const QTreeWidgetItem *item = getTreeWidgetItemFromUdi(this,udi);
   if(item == nullptr) return;

Modules/devinfo/devicelisting.h

@@ -88,7 +88,7 @@ class DeviceListing : public QTreeWidget
   public Q_SLOTS:
     void itemActivatedSlot(QTreeWidgetItem *,const int);
     void deviceAddedSlot(const QString &);
-    void deviceRemovedSlot(const QString);
+    void deviceRemovedSlot(const QString &);
     void collapseAllDevicesSlot();
     void expandAllDevicesSlot();
     void showAllDevicesSlot();

Modules/devinfo/devinfo.cpp

@@ -92,7 +92,7 @@ DevInfoPlugin::~DevInfoPlugin()
   delete layout; 
 }
   
-void DevInfoPlugin::updateStatus(const QString message) 
+void DevInfoPlugin::updateStatus(const QString &message)
 {  
   udiStatus->setText(message);
 }

Modules/devinfo/devinfo.h

@@ -46,7 +46,7 @@ class DevInfoPlugin : public KCModule
     DevInfoPlugin(QWidget *parent, const QVariantList &);
     ~DevInfoPlugin();
     
-    void updateStatus(const QString uid);
+    void updateStatus(const QString &uid);
     
   private:
     QGridLayout *layout;

Modules/devinfo/soldevice.h

@@ -99,8 +99,8 @@ class SolDevice : public QTreeWidgetItem
     void setDeviceToolTip(const QString &);
 
     virtual QVListLayout *infoPanelLayout();
-    virtual void addItem(Solid::Device dev) { new SolDevice(this,dev); };
-    virtual void refreshName() { setDefaultDeviceText(); };
+    virtual void addItem(const Solid::Device &dev) { new SolDevice(this,dev); }
+    virtual void refreshName() { setDefaultDeviceText(); }
    
     QString udi() const;
     bool isDeviceSet();

Modules/opengl/opengl.cpp

@@ -100,7 +100,7 @@ void KCMOpenGL::treeWidgetChanged() {
     glinfoTreeWidget->resizeColumnToContents(1);
 }
 
-QTreeWidgetItem *newItem(QTreeWidgetItem *parent, QTreeWidgetItem *preceding, QString textCol1, QString textCol2 = QString()) {
+QTreeWidgetItem *newItem(QTreeWidgetItem *parent, QTreeWidgetItem *preceding, const QString &textCol1, const QString &textCol2 = QString()) {
     QTreeWidgetItem *newItem;
     if ((parent == NULL) && (preceding == NULL)) {
 	newItem = new QTreeWidgetItem();
@@ -178,7 +178,7 @@ static int ReadPipe(const QString &FileName, QStringList &list)
 
 #if defined(Q_OS_LINUX)
 
-#define INFO_DRI "/proc/dri/0/name"
+#define INFO_DRI QStringLiteral("/proc/dri/0/name")
 
 static bool get_dri_device()
 {

Modules/usbview/usbdb.cpp

@@ -44,7 +44,7 @@ USBDB::USBDB() {
 		QRegExp prot(QStringLiteral("\\s+[0-9a-fA-F][0-9a-fA-F]  "));
 		while (!ts.atEnd()) {
 			line = ts.readLine();
-			if (line.left(1) == QLatin1String("#") || line.trimmed().isEmpty())
+            if (!line.isEmpty() && (line.at(0) == QLatin1String("#") || line.trimmed().isEmpty()))
 				continue;
 
 			// skip AT lines

kcmtreeitem.cpp

@@ -23,7 +23,7 @@
 //Local
 #include "kcmtreeitem.h"
 
-KcmTreeItem::KcmTreeItem(const KService::Ptr module, KcmTreeItem *parent) : m_parent(parent), m_module(module),
+KcmTreeItem::KcmTreeItem(const KService::Ptr &module, KcmTreeItem *parent) : m_parent(parent), m_module(module),
   m_moduleInfo(new KCModuleInfo(m_module))
 {
 }

kcmtreeitem.h

@@ -41,7 +41,7 @@ class KcmTreeItem
         * @param module pointer to KCM module
         * @param parent objects parent
         */
-        explicit KcmTreeItem(const KService::Ptr module, KcmTreeItem *parent=0);
+        explicit KcmTreeItem(const KService::Ptr &module, KcmTreeItem *parent=0);
 
         /**
         * KCM Tree Item for InfoKcmModel. Holds information about a KCM