I made a separate report of the 5.7-rc2 kernel bug to ubuntu-bug linux as you requested. I will also try to monitor the upstream rc kernels and run tests on them as you have requested.
I agree that the slow boot bug is likely connected to the AMD video card in my iMac, and thus to the amdgpu driver. I say that because I also have a 2011 iMac with a much older AMD Radeon video card (6770M), and it has no trouble with the 5.4 kernel in Ubuntu 20.04, nor with any of the kernels that came with 18.04, 18.10, 19.04 or 19.10. If the amdgpu powerplay failing to send message is the problem, is there an easy fix for this? I did look at the changelog for the 5.3-rc1 kernel (the first with the slow boot). There were a lot of changes related to amd and amdgpu by at least 25 people, but I have no idea how to figure out which, if any, of these changes is causing the slow boot. -- 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/1874104 Title: Very slow boot, wake from sleep and shutdown with 5.4 kernel Status in linux package in Ubuntu: Confirmed Bug description: I upgraded a Ubuntu 18.04 installation to 20.04 beta on my late 2015 5k 27" iMac. The new 5.4 kernel was installed and has been updated a few times. The former LTS kernel (4.15) was retained. When I start up the computer with the new kernel, the process is very slow and it takes about 2 1/2 minutes to get to a working desktop. Doing the same startup with the old 4.15 kernel (in the 20.04 beta) takes approximately 25 seconds to a working desktop. Similarly, changing display settings, waking from sleep and shutting down the computer all take several minutes with the 5.4 kernel, vs 10-30 seconds with the 4.15 kernel. To provide more information, I tried starting up this computer with the 5.3 kernel from a 19.10 live USB, and from a 5.0 kernel in the Peppermint Linux live USB that is based on Ubuntu. The 5.3 kernel is as slow as the 5.4 kernel, whereas the 5.0 kernel works similarly to the 4.15 LTS kernel. I suspect that the problem relates to the Radeon m9 390x video card in my iMac, but I have no idea what might have changed in the newer kernels to affect their compatibility with this iMac. ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: linux-image-5.4.0-25-generic 5.4.0-25.29 ProcVersionSignature: Ubuntu 5.4.0-25.29-generic 5.4.30 Uname: Linux 5.4.0-25-generic x86_64 ApportVersion: 2.20.11-0ubuntu27 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC2: mfox 2497 F.... pulseaudio /dev/snd/controlC0: mfox 2497 F.... pulseaudio /dev/snd/controlC1: mfox 2497 F.... pulseaudio CasperMD5CheckResult: skip CurrentDesktop: ubuntu:GNOME Date: Tue Apr 21 10:55:18 2020 HibernationDevice: # RESUME=UUID=5e4ca488-e781-4ee7-aeb3-8adc968cd22a InstallationDate: Installed on 2018-05-09 (712 days ago) InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426) MachineType: Apple Inc. iMac17,1 ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_CA.UTF-8 SHELL=/bin/bash ProcFB: 0 amdgpudrmfb ProcKernelCmdLine: \boot\vmlinuz-5.4.0-25-generic ro root=UUID=0559983a-7175-4ab1-af46-7a117ee78ead initrd=boot\initrd.img-5.4.0-25-generic RelatedPackageVersions: linux-restricted-modules-5.4.0-25-generic N/A linux-backports-modules-5.4.0-25-generic N/A linux-firmware 1.187 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 01/31/2020 dmi.bios.vendor: Apple Inc. dmi.bios.version: 176.0.0.0.0 dmi.board.name: Mac-B809C3757DA9BB8D dmi.board.vendor: Apple Inc. dmi.board.version: iMac17,1 dmi.chassis.type: 9 dmi.chassis.vendor: Apple Inc. dmi.chassis.version: Mac-B809C3757DA9BB8D dmi.modalias: dmi:bvnAppleInc.:bvr176.0.0.0.0:bd01/31/2020:svnAppleInc.:pniMac17,1:pvr1.0:rvnAppleInc.:rnMac-B809C3757DA9BB8D:rvriMac17,1:cvnAppleInc.:ct9:cvrMac-B809C3757DA9BB8D: dmi.product.family: iMac17,1 dmi.product.name: iMac17,1 dmi.product.version: 1.0 dmi.sys.vendor: Apple Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1874104/+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
