Hi towo
I tried some more reboots and surprisingly the pc start**. Before that there was nothing after the grub menu and the monitor tuns of.
edit**: I have a second Monitor witch is connected to the pc via VAG, but this monitor is and was deactivated in the system-settings and not used in the last weeks. So switched him on after the main monitor "dies" and there was the login-screen. So I can login on this second monitor, but after the login there is no more video signal and the main monitor starts again.
This confusing behaviour is only when I boot with 4.3.0....
dmesg | egrep -i "intel|i915" (with kernel 4.3)
[ 0.000000] ACPI: DMAR 0x00000000CC9A8D78 0000B8 (v01 INTEL SNB 00000001 INTL 00000001)
[ 0.000000] Reserving Intel graphics stolen memory at 0xcf200000-0xdf1fffff
[ 0.043576] smpboot: CPU0: Intel(R) Core(TM) i5-3570 CPU @ 3.40GHz (family: 0x6, model: 0x3a, stepping: 0x9)
[ 0.043586] Performance Events: PEBS fmt1+, 16-deep LBR, IvyBridge events, full-width counters, Intel PMU driver.
[ 0.163832] perf_event_intel: PMU erratum BJ122, BV98, HSD29 workaround disabled, HT off
[ 0.204921] pci 0000:00:02.0: BIOS left Intel GPU interrupts enabled; disabling
[ 0.456690] intel_idle: MWAIT substates: 0x1120
[ 0.456691] intel_idle: v0.4 model 0x3A
[ 0.456692] intel_idle: lapic_timer_reliable_states 0xffffffff
[ 0.484102] Intel P-state driver initializing.
[ 1.988525] iTCO_wdt: Intel TCO WatchDog Timer Driver v1.11
[ 2.043300] [drm] Initialized i915 1.6.0 20150731 for 0000:00:02.0 on minor 0
[ 2.106175] input: HDA Intel PCH Front Mic as /devices/pci0000:00/0000:00:1b.0/sound/card0/input10
[ 2.106211] input: HDA Intel PCH Rear Mic as /devices/pci0000:00/0000:00:1b.0/sound/card0/input11
[ 2.106241] input: HDA Intel PCH Line as /devices/pci0000:00/0000:00:1b.0/sound/card0/input12
[ 2.106270] input: HDA Intel PCH Line Out as /devices/pci0000:00/0000:00:1b.0/sound/card0/input13
[ 2.106299] input: HDA Intel PCH Front Headphone as /devices/pci0000:00/0000:00:1b.0/sound/card0/input14
[ 2.106329] input: HDA Intel PCH HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:1b.0/sound/card0/input15
[ 2.674728] [drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcoder A
[ 2.674733] [drm:cpt_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun