Created attachment 120710 [details] dmesg(dmr.debug=0xe) I'm using the kernel from drm-intel-nightly branch on the 2015-12-19, with the i915.fastboot=1 module parameter (otherwise I get bug 92878). The 4K laptop display shows some tearing, but it's functional. Sometimes there is a random hotplug event ([drm:intel_get_hpd_pins] hotplug event received), then it goes into training and the display goes black, I can't get it back unless I reboot the laptop. I didn't plug or do anything to trigger that hotplug event.
Can you please give me your hardware configuration? Which monitor are you using? Are you using any adaptors etc.
I was trying to reproduce this issue over a BDW platform with the following configuration: 4k Display through MiniDP connection. Ubuntu 16.04, components: ++ Date : jun-WW24-01-11:31:29 --> Component : drm url : http://cgit.freedesktop.org/mesa/drm tag : libdrm-2.4.68 commit : fc09c5a author : Kenneth Graunke <kenneth@whitecape.org> age : 6 weeks ago --> Component : mesa url : http://cgit.freedesktop.org/mesa/mesa tag : mesa-11.2.2 commit : 3a9f628 author : Emil Velikov <emil.velikov@collabora.com> age : 4 weeks ago --> Component : xf86-video-intel url : http://cgit.freedesktop.org/xorg/driver/xf86-video-intel tag : 2.99.917 commit : baec802 author : Chris Wilson <chris@chris-wilson.co.uk> age : 1 year 6 months ago --> Component : libva url : http://cgit.freedesktop.org/libva/ tag : libva-1.7.1.pre1 commit : 453876f author : Xiang Haihao <haihao.xiang@intel.com> age : 4 days ago --> Component : vaapi (intel-driver) url : http://cgit.freedesktop.org/vaapi/intel-driver tag : 1.7.1.pre1 commit : 2975480 author : Xiang Haihao <haihao.xiang@intel.com> age : 4 days ago --> Component : cairo url : http://cgit.freedesktop.org/cairo tag : 1.15.2 commit : db8a7f1 author : Bryce Harrington <bryce@osg.samsung.com> age : 6 months ago --> Component : xserver url : http://cgit.freedesktop.org/xorg/xserver tag : xorg-server-1.18.3 commit : 9454cd5 author : Adam Jackson <ajax@redhat.com> age : 9 weeks ago --> Component : intel-gpu-tools url : http://cgit.freedesktop.org/xorg/app/intel-gpu-tools tag : intel-gpu-tools-1.15 commit : 3ce58b6 author : Marius Vlad <marius.c.vlad@intel.com> age : 6 days ago Kernel 4.7 nightly from: http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-intel-nightly/2016-06-28-yakkety/ I was not able to reproduce the bug, Please confirm at your side.
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