Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.3.4 (KDE 4.3.4)
Qt Version: 4.5.3
Operating System: Linux 2.6.32-ARCH i686

What I was doing when the application crashed:
My screen may unexpactable be totally white but i still can tune it's backlight 
by hotkey.
But i can't switch to tty1~6

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 1 (Thread 0xb56db700 (LWP 4307))]

Thread 2 (Thread 0xa7e7fb70 (LWP 4308)):
#0  0xb78ca424 in __kernel_vsyscall ()
#1  0xb7660e55 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#2  0xb76bf067 in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib/libQtCore.so.4
#3  0xb5e73f22 in ?? () from /usr/lib/libQtNetwork.so.4
#4  0xb76be052 in ?? () from /usr/lib/libQtCore.so.4
#5  0xb765c8ac in start_thread () from /lib/libpthread.so.0
#6  0xb60f001e in clone () from /lib/libc.so.6

Thread 1 (Thread 0xb56db700 (LWP 4307)):
[KCrash Handler]
#6  0xb63c41cd in QWidget::mapToParent(QPoint const&) const () from /usr/lib/libQtGui.so.4
#7  0xb63c424b in QWidget::mapTo(QWidget*, QPoint const&) const () from /usr/lib/libQtGui.so.4
#8  0xa7f8cb46 in SystemTray::X11EmbedPainter::performUpdates() () from /usr/lib/kde4/plasma_applet_systemtray.so
#9  0xa7f8ce91 in SystemTray::X11EmbedPainter::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/kde4/plasma_applet_systemtray.so
#10 0xb77c1fdc in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#11 0xb77c2c12 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#12 0xb77fc2d7 in QTimer::timeout() () from /usr/lib/libQtCore.so.4
#13 0xb77c768e in QTimer::timerEvent(QTimerEvent*) () from /usr/lib/libQtCore.so.4
#14 0xb77bc18f in QObject::event(QEvent*) () from /usr/lib/libQtCore.so.4
#15 0xb637d924 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#16 0xb638500c in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#17 0xb6dc060a in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#18 0xb77ac5bb in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#19 0xb77d9efe in ?? () from /usr/lib/libQtCore.so.4
#20 0xb77d7007 in ?? () from /usr/lib/libQtCore.so.4
#21 0xb5f84378 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#22 0xb5f87bf0 in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#23 0xb5f87d23 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#24 0xb77d6d25 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#25 0xb641b705 in ?? () from /usr/lib/libQtGui.so.4
#26 0xb77aaba9 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#27 0xb77aaffa in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#28 0xb77ad46f in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#29 0xb637d7a7 in QApplication::exec() () from /usr/lib/libQtGui.so.4
#30 0xb4142b7d in kdemain () from /usr/lib/libkdeinit4_plasma-desktop.so
#31 0x0804de42 in _start ()

Reported using DrKonqi