Full system lockup after attaching external monitor

[knz]

Running on a recently acquired Lenovo Yoga 260.

How to reproduce:
1. plug external screen
2. activate/configure monitor (either using GUI or xrandr)
3. set relative position of ext monitor to something else than the default (e.g. above or below)
4. move cursor from laptop screen to external screen
5. move cursor back from extrernal screen to laptop screen

At this point a full system freeze occurs. Cannot switch to console, no kernel error (crashkernel does not activate), no trace in dmesg/Xorg.log etc. Even remote ssh sessions onto the computer freeze, so no extra information can be gathered this way.

The lock-up does not occur if any of the steps above are omitted:
- no issue if the external monitor is not activated
- no issue if the relative position is not changed
- no issue if the mouse cursor stays on the laptop screen where it was initially
- no issue if the mouse cursor iis moved from the laptop screen to the external screen and stays there

**Also the issue does not occur if the external monitor is already plugged before boot, and the resolution and position is only set once upon Xorg start-up**. In other words it is possible to use an external monitor as long as 1) it is plugged before boot 2) the Xorg conf contains explicit entries to set the resolution and position.

The issue can be reproduced reliably on both a fresh 15.10 install, any stock Ubuntu kernel, and the mainline PPA kernels (up to and including the latest 4.6-rc2). Also reproduces reliably with both the base intel drivers shipped with 15.10 and those provided by Intel's linux-installer.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: xorg 1:7.7+7ubuntu4
Uname: Linux 4.6.0-040600rc2-generic x86_64
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
Date: Wed Apr 6 11:31:13 2016
DistUpgraded: Fresh install
DistroCodename: wily
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes
GpuHangFrequency: Continuously
GpuHangReproducibility: Yes, I can easily reproduce it
GpuHangStarted: Since before I upgraded
GraphicsCard:
 Intel Corporation Sky Lake Integrated Graphics [8086:1916] (rev 07) (prog-if 00 [VGA controller])
   Subsystem: Lenovo Device [17aa:2237]
InstallationDate: Installed on 2016-03-13 (23 days ago)
InstallationMedia: Xubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
MachineType: LENOVO 20FD0004US
ProcEnviron:
 TERM=screen
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/usr/bin/zsh
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.6.0-040600rc2-generic root=/dev/mapper/xubuntu--vg-root ro quiet splash intel_idle.max_cstate=1 crashkernel=384M-:200M
SourcePackage: xorg
Symptom: display
Title: Xorg freeze
UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev'
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/05/2015
dmi.bios.vendor: LENOVO
dmi.bios.version: N1GET34W (1.11 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20FD0004US
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40697 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrN1GET34W(1.11):bd11/05/2015:svnLENOVO:pn20FD0004US:pvrThinkPadYoga260:rvnLENOVO:rn20FD0004US:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.name: 20FD0004US
dmi.product.version: ThinkPad Yoga 260
dmi.sys.vendor: LENOVO
version.compiz: compiz N/A
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.65+git20151026.c745e541-0ubuntu0ricotz~wily
version.libgl1-mesa-dri: libgl1-mesa-dri 11.0.4-1intel1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.0.4-1intel1
version.xserver-xorg-core: xserver-xorg-core 2:1.17.2-1ubuntu9.1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.9.2-1ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.5.99+git20150521.d64a13eb-0ubuntu0ricotz
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20151202.da9ad388-0ubuntu0sarvatt
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.11+git20150926.1ff13a92-0ubuntu0sarvatt
xserver.bootTime: Wed Apr 6 11:25:42 2016
xserver.configfile: None
xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.17.2-1ubuntu9.1
xserver.video_driver: intel

[knz (knz)]

Note that although the debug files mention that the kernel was booted with "intel_idle.max_cstate=1 " the issue reproduces with or without this parameter.

[knz (knz)]

Another note:
The current dmesg reports an intel driver warning:
Apr 06 11:25:40 hostname kernel: WARNING: CPU: 1 PID: 6 at /home/kernel/COD/linux/drivers/gpu/drm/i915/intel_pm.c:3572 skl_update_other_pipe_wm+0x16c/0x180 [i915]

followed by a stack trace. This is likely to be irrelevant to the issue: this only started to appear after upgrading to intel-provided drivers. This warning was not present just after installing Ubuntu 15.10. However the issue reported in this bug report was happening both before and after the intel driver upgrade.

[knz (knz)]

The issue persists with kernel 4.6-rc4.

However it disappears (fixed?) with the intel nightly drivers as of April 16th 2016 (from http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-intel-nightly/2016-04-16-wily/ ).

[penalvch (penalvch)]

knz, thank you for reporting this and helping make Ubuntu better.

To see if this is already resolved, could you please test http://cdimage.ubuntu.com/daily-live/current/ and advise to the results?

[Launchpad Janitor (janitor)]

[Expired for xorg (Ubuntu) because there has been no activity for 60 days.]