Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?
Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.19 kernel[0]. If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'. If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'. Once testing of the upstream kernel is complete, please mark this bug as "Confirmed". Thanks in advance. [0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.19-rc3 ** Changed in: linux (Ubuntu) Importance: Undecided => Medium ** Changed in: linux (Ubuntu) Status: Confirmed => Incomplete -- 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/1791913 Title: HP EliteBook 840 G5 only able to initialise displays on first docking Status in linux package in Ubuntu: Incomplete Bug description: I'm running a HP EliteBook 840 G5 and HP UlstraSlim Docking Station with two external DisplayPort displays (both 1080p). Upon docking the machine for the first time the two external displays come up as expected. Upon removal the internal display continues to work as expected, but the external displays never come up. Dock verified good and working with another machine. Upon disconnect the following is emitted to the journal: Sep 11 10:13:01 hlc002155 kernel: [drm:intel_dp_start_link_train [i915]] *ERROR* failed to enable link training Sep 11 10:13:02 hlc002155 kernel: [drm:intel_mst_pre_enable_dp [i915]] *ERROR* failed to allocate vcpi Upon reconnect the following: Sep 11 10:13:15 hlc002155 kernel: [drm:intel_wait_ddi_buf_idle [i915]] *ERROR* Timeout waiting for DDI BUF C idle bit I found some issues that seem related: * https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1552040 * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1777863 The workaround described in https://bugs.launchpad.net/ubuntu/+source /xserver-xorg-video-intel/+bug/1552040/comments/17 didn't seem to work for me. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.15.0-34-generic 4.15.0-34.37 ProcVersionSignature: Ubuntu 4.15.0-34.37-generic 4.15.18 Uname: Linux 4.15.0-34-generic x86_64 ApportVersion: 2.20.9-0ubuntu7.3 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: lukecarrier 2534 F.... pulseaudio CurrentDesktop: GNOME Date: Tue Sep 11 10:14:12 2018 HibernationDevice: RESUME=UUID=f10979d4-f0c5-4e4c-b978-a2eee4dd7109 InstallationDate: Installed on 2018-07-18 (54 days ago) InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426) Lsusb: Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 006: ID 04ca:706e Lite-On Technology Corp. Bus 001 Device 005: ID 138a:00ab Validity Sensors, Inc. Bus 001 Device 003: ID 8087:0a2b Intel Corp. Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: HP HP EliteBook 840 G5 ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_GB.UTF-8 SHELL=/bin/bash ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.15.0-34-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash vt.handoff=1 RelatedPackageVersions: linux-restricted-modules-4.15.0-34-generic N/A linux-backports-modules-4.15.0-34-generic N/A linux-firmware 1.173.1 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 06/05/2018 dmi.bios.vendor: HP dmi.bios.version: Q78 Ver. 01.01.08 dmi.board.name: 83B2 dmi.board.vendor: HP dmi.board.version: KBC Version 04.50.00 dmi.chassis.type: 10 dmi.chassis.vendor: HP dmi.modalias: dmi:bvnHP:bvrQ78Ver.01.01.08:bd06/05/2018:svnHP:pnHPEliteBook840G5:pvr:rvnHP:rn83B2:rvrKBCVersion04.50.00:cvnHP:ct10:cvr: dmi.product.family: 103C_5336AN HP EliteBook dmi.product.name: HP EliteBook 840 G5 dmi.sys.vendor: HP To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1791913/+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
