laptop locks up and has to be powered off after logging out from kde plasma. happens only when hdmi monitor is connected.

Portage 2.2.26 (python 3.4.3-final-0, default/linux/amd64/13.0/desktop/plasma/systemd, gcc-5.3.0, glibc-2.22-r2, 4.5.0-rc4+ x86_64)
=================================================================
System uname: Linux-4.5.0-rc4+-x86_64-Intel-R-_Core-TM-_i7-5600U_CPU_@_2.60GHz-with-gentoo-2.2
KiB Mem:     8078624 total,   3440192 free
KiB Swap:    1023996 total,   1023996 free
sh bash 4.3_p42-r1
ld GNU ld (Gentoo 2.25.1 p1.1) 2.25.1
distcc 3.2rc1 x86_64-pc-linux-gnu [enabled]
ccache version 3.1.9 [enabled]
app-shells/bash:          4.3_p42-r1::gentoo
dev-java/java-config:     2.2.0::gentoo
dev-lang/perl:            5.20.2::gentoo
dev-lang/python:          2.7.10-r1::gentoo, 3.4.3-r1::gentoo
dev-util/ccache:          3.1.9-r4::gentoo
dev-util/cmake:           3.3.1-r1::gentoo
dev-util/pkgconfig:       0.28-r2::gentoo
sys-apps/baselayout:      2.2::gentoo
sys-apps/openrc:          0.19.1::gentoo
sys-apps/sandbox:         2.10-r1::gentoo
sys-devel/autoconf:       2.13::gentoo, 2.69::gentoo
sys-devel/automake:       1.11.6-r1::gentoo, 1.12.6::gentoo, 1.14.1::gentoo, 1.15::gentoo
sys-devel/binutils:       2.25.1-r1::gentoo
sys-devel/gcc:            5.3.0::gentoo
sys-devel/gcc-config:     1.7.3::gentoo
sys-devel/libtool:        2.4.6::gentoo
sys-devel/make:           4.1-r1::gentoo
sys-kernel/linux-headers: 4.3::gentoo (virtual/os-headers)
sys-libs/glibc:           2.22-r2::gentoo
Repositories:

gentoo
    location: /usr/portage
    sync-type: git
    sync-uri: https://anongit.gentoo.org/git/repo/gentoo.git
    priority: -1000

x-portage
    location: /usr/local/portage
    masters: gentoo
    priority: 0

kde
    location: /var/lib/layman/kde
    sync-type: laymansync
    sync-uri: git://anongit.gentoo.org/proj/kde.git
    masters: gentoo
    priority: 50

x11
    location: /var/lib/layman/x11
    sync-type: laymansync
    sync-uri: git://anongit.gentoo.org/proj/x11.git
    masters: gentoo
    priority: 50

Installed sets: @kde-frameworks, @kde-plasma
ACCEPT_KEYWORDS="amd64"
ACCEPT_LICENSE="*"
CBUILD="x86_64-pc-linux-gnu"
CFLAGS="-march=broadwell -O2 -pipe -fomit-frame-pointer"
CHOST="x86_64-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/share/config /usr/share/gnupg/qualified.txt /usr/share/maven-bin-3.3/conf /usr/share/themes/oxygen-gtk/gtk-2.0 /usr/share/themes/oxygen-gtk/gtk-3.0 /var/lib/hsqldb"
CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/dconf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo"
CXXFLAGS="-march=broadwell -O2 -pipe -fomit-frame-pointer"
DISTDIR="/usr/portage/distfiles"
FCFLAGS="-O2 -pipe"
FEATURES="assume-digests binpkg-logs ccache config-protect-if-modified distcc distlocks ebuild-locks fixlafiles merge-sync news parallel-fetch preserve-libs protect-owned sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync xattr"
FFLAGS="-O2 -pipe"
GENTOO_MIRRORS="http://distfiles.gentoo.org"
LANG="en_US.utf8"
LDFLAGS="-Wl,-O1 -Wl,--as-needed"
MAKEOPTS="-j12 -l4"
PKGDIR="/usr/portage/packages"
PORTAGE_CONFIGROOT="/"
PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --omit-dir-times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages"
PORTAGE_TMPDIR="/tmp"
USE="256-color X a52 aac aalib acpi adns alaw alsa alt-font-width amd64 archive asf aspell async autoipd autoreplace avahi bash-completion bluetooth branding btrfs bzip2 c++0x cairo caps cdda cdinstall cdr chroot cli client-libs cracklib crypt cryptsetup cups curl custom-cflags custom-optimization cxx dbus declarative dhcp disk-partition divx divx4linux dri dri3 dts dvd dvdr egl emerald enca encode evdev exif faac farstream ffmpeg firefox flac focused-urgency font-styles fortran fpm fts3 fuse g722 gallium gbm gd gdbm gecko-sdk geoclue geoip gif glamor gles2 glibc-omitfp glitz gmedia gnutls google gphoto2 gps gsm gstreamer gudev hardcoded-tables hddtemp hidpi history hpn hwdb ibmacpi iconv id3tag imagemagick imap imlib inotify introspection iproute2 ithreads jabber javascript jpeg kde kdehiddenvisibility kdenlive kdepim kdexdeltas kipi lame laptop lcdfilter lcms libcaca libkms libnotify lm_sensors logrotate lzma lzo mad matroska minizip mmx mmxext mng modemmanager modules mousewheel mozbranding moznocompose moznoirc moznomail mozsvg mp3 mp4 mpeg mtp multilib musicbrainz mysql ncurses networkmanager nfsv3 nonfsv4 nptl nsplugin offensive ogg openconnect opengl openmp optimized-qmake otr pam pango pch pcre pdf perl phonon pic plasma png pnp policykit postproc ppds pulseaudio python python3 qml qt3support qt4 qt5 rar rdesktop readline rpc rss rtc rtmp samba sasl scrobbler sdl seccomp secondary-wheel secure-delete semantic-desktop session shared-dricore sip sipim smi smime smtp sna snmp speex spell sqlite srt sse sse2 sse3 ssl ssse3 stroke svg system-cairo system-ffmpeg system-icu system-jpeg system-libvpx systemd telepathy theora thinkpad threads tidy tiff tordns truetype udev udisks udisks2 ulaw uncommon-eap-types unicode upower urandom usb userlocales v4l2 vaapi vim vim-syntax vnc vorbis vpx wayland wayland-compositor webkit widgets wifi windeco wma wmp x264 xattr xcb xcomposite xforms xml xmp xosd xrandr xscreensaver xv xvfb xvid xwayland yahoo zeroconf zip zlib" ABI_X86="64 32" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" APACHE2_MODULES="authn_core authz_core socache_shmcb unixd actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" CALLIGRA_FEATURES="kexi words flow plan sheets stage tables krita karbon braindump author" CAMERAS="ptp2" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" CPU_FLAGS_X86="aes avx avx2 fma3 mmx mmxext popcnt sse sse2 sse3 sse4_1 sse4_2 ssse3" DRACUT_MODULES="btrfs" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf superstar2 timing tsip tripmate tnt ublox ubx" GRUB_PLATFORMS="pc efi-64" INPUT_DEVICES="keyboard evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer pdfimport wiki-publisher" LINGUAS="en bg" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php5-5" PYTHON_SINGLE_TARGET="python2_7" PYTHON_TARGETS="python2_7 python3_4" RUBY_TARGETS="ruby20 ruby21" USERLAND="GNU" VIDEO_CARDS="intel i965" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account"
Unset:  CC, CPPFLAGS, CTARGET, CXX, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LC_ALL, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, USE_PYTHON