This isn't a kernel issue - I don't have an answer on the why for being forced offline but it's the not a kernel bug.
-- 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/1827335 Title: Unable to put offline CPU back online on Bionic/B-hwe-edge P9 Status in The Ubuntu-power-systems project: Incomplete Status in linux package in Ubuntu: Incomplete Bug description: You will see these CPUs in offline state after boot. ubuntu@baltar:~$ cat /sys/devices/system/cpu/offline 156-159 ubuntu@baltar:~$ echo 1 | sudo tee /sys/devices/system/cpu/cpu156/online 1 tee: /sys/devices/system/cpu/cpu156/online: Invalid argument ubuntu@baltar:~$ echo 1 | sudo tee /sys/devices/system/cpu/cpu157/online 1 tee: /sys/devices/system/cpu/cpu157/online: Invalid argument ubuntu@baltar:~$ echo 1 | sudo tee /sys/devices/system/cpu/cpu158/online 1 tee: /sys/devices/system/cpu/cpu158/online: Invalid argument ubuntu@baltar:~$ echo 1 | sudo tee /sys/devices/system/cpu/cpu159/online 1 tee: /sys/devices/system/cpu/cpu159/online: Invalid argument ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-5.0.0-14-generic 5.0.0-14.15~18.04.1+signed1 ProcVersionSignature: Ubuntu 5.0.0-14.15~18.04.1-generic 5.0.6 Uname: Linux 5.0.0-14-generic ppc64le ApportVersion: 2.20.9-0ubuntu7.6 Architecture: ppc64el Date: Thu May 2 06:46:36 2019 ProcLoadAvg: 0.00 0.00 0.00 1/1298 6496 ProcSwaps: Filename Type Size Used Priority /swap.img file 8388544 0 -2 ProcVersion: Linux version 5.0.0-14-generic (buildd@bos02-ppc64el-014) (gcc version 7.3.0 (Ubuntu 7.3.0-16ubuntu3)) #15~18.04.1-Ubuntu SMP Thu Apr 25 18:55:27 UTC 2019 SourcePackage: linux-signed-hwe-edge UpgradeStatus: No upgrade log present (probably fresh install) VarLogDump_list: total 0 cpu_cores: Number of cores present = 40 cpu_coreson: Number of cores online = 39 cpu_dscr: DSCR is 16 cpu_freq: min: 2.862 GHz (cpu 79) max: 2.945 GHz (cpu 81) avg: 2.903 GHz cpu_runmode: Could not retrieve current diagnostics mode, No kernel interface to firmware cpu_smt: SMT=4 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-power-systems/+bug/1827335/+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
