The 4.7-rc1 kernel was not bootable on my system. However, I have been testing with 4.6.0-996-generic #201605082201 from drm-next and the behavior is better. With the drm-next kernel, I am able to dock/undock the laptop multiple times without a freeze and the displays are recognized and can be setup. The configured display layout is applied successfully on docking, unlike with the 4.4.0-22 kernel. I do have one persistent issue with the drm-next kernel, I have to change to a VT and back to get display output after docking - but I don't think its related to this issue. This intel stuff sure seems like a mess.
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1568573 Title: [Lenovo Thinkpad T460] Ultra Dock external displays not detected after suspend/resume cycle Status in linux package in Ubuntu: Incomplete Bug description: Hello, System is Thinkpad T460, Skylake graphics, Thinkpad Ultra dock. DVI and HDMI displays connected via dock. 4.4.0-18. After a suspend-resume cycle, when the laptop is docked the dock connected external displays are not initialized/connected. If I disconnect the displays from the dock and connect them directly to the laptop, they are initialized successfully and can be configured via xrandr etc. If the laptop is power cycled, the displays can be used normally until the next suspend-resume cycle. Example from relevant dmesg: [drm:intel_dp_link_training_clock_recovery [i915_bpo]] *ERROR* too many voltage retries, give up [drm:intel_dp_link_training_clock_recovery [i915_bpo]] *ERROR* too many voltage retries, give up [drm:intel_dp_link_training_clock_recovery [i915_bpo]] *ERROR* too many voltage retries, give up [drm:intel_dp_start_link_train [i915_bpo]] *ERROR* failed to train DP, aborting [drm:intel_dp_set_idle_link_train [i915_bpo]] *ERROR* Timed out waiting for DP idle patterns [drm:intel_dp_link_training_clock_recovery [i915_bpo]] *ERROR* too many voltage retries, give up [drm:intel_dp_link_training_clock_recovery [i915_bpo]] *ERROR* too many voltage retries, give up [drm:intel_dp_link_training_clock_recovery [i915_bpo]] *ERROR* too many voltage retries, give up ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: linux-image-4.4.0-18-generic 4.4.0-18.34 ProcVersionSignature: Ubuntu 4.4.0-18.34-generic 4.4.6 Uname: Linux 4.4.0-18-generic x86_64 ApportVersion: 2.20.1-0ubuntu1 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: ryan 1838 F.... pulseaudio Date: Sun Apr 10 09:39:32 2016 HibernationDevice: RESUME=UUID=04e04e17-3976-4daa-a1dd-2dd369aee83d InstallationDate: Installed on 2015-09-21 (201 days ago) InstallationMedia: It Lsusb: Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: LENOVO 20FNCTO1WW ProcEnviron: TERM=xterm PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-18-generic root=/dev/mapper/it--vg-root ro quiet PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon. RelatedPackageVersions: linux-restricted-modules-4.4.0-18-generic N/A linux-backports-modules-4.4.0-18-generic N/A linux-firmware 1.157 SourcePackage: linux UpgradeStatus: Upgraded to xenial on 2016-02-24 (45 days ago) dmi.bios.date: 03/09/2016 dmi.bios.vendor: LENOVO dmi.bios.version: R06ET35W (1.09 ) dmi.board.asset.tag: Not Available dmi.board.name: 20FNCTO1WW 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:bvrR06ET35W(1.09):bd03/09/2016:svnLENOVO:pn20FNCTO1WW:pvrThinkPadT460:rvnLENOVO:rn20FNCTO1WW:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone: dmi.product.name: 20FNCTO1WW dmi.product.version: ThinkPad T460 dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1568573/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
