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 v4.18 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/v4.18-rc8 ** Package changed: linux-signed (Ubuntu) => linux (Ubuntu) ** Changed in: linux (Ubuntu) Importance: Undecided => Medium -- 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/1785326 Title: The booting is too long with drm_atomic_helper_wait_for_dependencies errors (xenial+hwe,bionic). Status in linux package in Ubuntu: New Bug description: 1,2) Please see the apport attachments 3) Fast booting without errors as with xenial non-hwe kernels 4) The booting is too long The errors are similar to this: [drm:drm_atomic_helper_wait_for_dependencies [drm_kms_helper]] *ERROR* [CRTC:41:pipe B] flip_done timed out [drm:drm_atomic_helper_wait_for_dependencies [drm_kms_helper]] *ERROR* [PLANE:35:plane B] flip_done timed out The errors appears on Toshiba Satellite L300-11Q. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.15.0-20-generic 4.15.0-20.21 ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17 Uname: Linux 4.15.0-20-generic x86_64 ApportVersion: 2.20.9-0ubuntu7 Architecture: amd64 CasperVersion: 1.394 CurrentDesktop: LXDE Date: Fri Aug 3 20:34:23 2018 LiveMediaBuild: Lubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426) ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=ru_RU.UTF-8 SHELL=/bin/bash SourcePackage: linux-signed UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1785326/+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