SRU: https://lists.ubuntu.com/archives/kernel- team/2019-November/105289.html
** Changed in: linux-oem-osp1 (Ubuntu Bionic) Status: New => In Progress ** Changed in: linux (Ubuntu Bionic) Status: Confirmed => In Progress ** Changed in: linux (Ubuntu Disco) Status: Confirmed => In Progress ** Description changed: + [SRU Justification] + + [Impact] + Some recent platform seem to have an unstable HPET, which is used to + calibrate TSC but turns out to mark an actual stable TSC clocksource as + unstable, and then fallback to that unstable HPET as main clocksource. A + previous fix was proposed in bug 1840239, which is then observed to hang + platforms with modern chipsets including Skylake and ApolloLake at early + boot stage when HPET is disabled. + + [Fix] + Commit c8c4076723da "x86/timer: Skip PIT initialization on modern chipsets" + included in v5.3-rc1 to be backported. + + [Test Case] + Boot with kernel built with this change, and see if it will hang right + after grub loaded initramfs image. + + [Regression Risk] + Low. This change detects the hardware that requires explicit PIT + initialization skip and skip it. For those unaffected systems, they + remain unaffected. + + ========== original description ========= + After upgrading kernel to linux-image-4.15.0-1061 (proposed), system hangs at very beginning of booting, leaving Grub messages "loading..." on the console. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.15.0-1060-oem 4.15.0-1060.69 ProcVersionSignature: Ubuntu 4.15.0-1060.69-oem 4.15.18 Uname: Linux 4.15.0-1060-oem x86_64 ApportVersion: 2.20.9-0ubuntu7.2 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/pcmC1D0c: u 1977 F...m pulseaudio /dev/snd/pcmC1D0p: u 1977 F...m pulseaudio /dev/snd/controlC0: u 1977 F.... pulseaudio CurrentDesktop: ubuntu:GNOME Date: Mon Nov 4 17:15:56 2019 InstallationDate: Installed on 2019-11-04 (0 days ago) InstallationMedia: Ubuntu 18.04 "Bionic" - Build amd64 LIVE Binary 20180608-09:38 MachineType: Dell Inc. Precision 5530 ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-1060-oem root=UUID=baa02b0a-d18f-41d2-9e2b-2d057742013c ro mem_sleep_default=deep nvidia-drm.modeset=1 quiet splash RelatedPackageVersions: linux-restricted-modules-4.15.0-1060-oem N/A linux-backports-modules-4.15.0-1060-oem N/A linux-firmware 1.173.9 SourcePackage: linux-oem UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 06/27/2019 dmi.bios.vendor: Dell Inc. dmi.bios.version: 1.12.0 dmi.board.name: 0184M4 dmi.board.vendor: Dell Inc. dmi.board.version: X00 dmi.chassis.type: 10 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvr1.12.0:bd06/27/2019:svnDellInc.:pnPrecision5530:pvr:rvnDellInc.:rn0184M4:rvrX00:cvnDellInc.:ct10:cvr: dmi.product.family: Precision dmi.product.name: Precision 5530 dmi.sys.vendor: Dell Inc. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-oem in Ubuntu. https://bugs.launchpad.net/bugs/1851216 Title: System hangs at early boot Status in linux package in Ubuntu: Confirmed Status in linux-oem package in Ubuntu: Invalid Status in linux-oem-osp1 package in Ubuntu: New Status in linux source package in Bionic: In Progress Status in linux-oem source package in Bionic: In Progress Status in linux-oem-osp1 source package in Bionic: In Progress Status in linux source package in Disco: In Progress Status in linux-oem source package in Disco: New Status in linux-oem-osp1 source package in Disco: New Bug description: [SRU Justification] [Impact] Some recent platform seem to have an unstable HPET, which is used to calibrate TSC but turns out to mark an actual stable TSC clocksource as unstable, and then fallback to that unstable HPET as main clocksource. A previous fix was proposed in bug 1840239, which is then observed to hang platforms with modern chipsets including Skylake and ApolloLake at early boot stage when HPET is disabled. [Fix] Commit c8c4076723da "x86/timer: Skip PIT initialization on modern chipsets" included in v5.3-rc1 to be backported. [Test Case] Boot with kernel built with this change, and see if it will hang right after grub loaded initramfs image. [Regression Risk] Low. This change detects the hardware that requires explicit PIT initialization skip and skip it. For those unaffected systems, they remain unaffected. ========== original description ========= After upgrading kernel to linux-image-4.15.0-1061 (proposed), system hangs at very beginning of booting, leaving Grub messages "loading..." on the console. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.15.0-1060-oem 4.15.0-1060.69 ProcVersionSignature: Ubuntu 4.15.0-1060.69-oem 4.15.18 Uname: Linux 4.15.0-1060-oem x86_64 ApportVersion: 2.20.9-0ubuntu7.2 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/pcmC1D0c: u 1977 F...m pulseaudio /dev/snd/pcmC1D0p: u 1977 F...m pulseaudio /dev/snd/controlC0: u 1977 F.... pulseaudio CurrentDesktop: ubuntu:GNOME Date: Mon Nov 4 17:15:56 2019 InstallationDate: Installed on 2019-11-04 (0 days ago) InstallationMedia: Ubuntu 18.04 "Bionic" - Build amd64 LIVE Binary 20180608-09:38 MachineType: Dell Inc. Precision 5530 ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-1060-oem root=UUID=baa02b0a-d18f-41d2-9e2b-2d057742013c ro mem_sleep_default=deep nvidia-drm.modeset=1 quiet splash RelatedPackageVersions: linux-restricted-modules-4.15.0-1060-oem N/A linux-backports-modules-4.15.0-1060-oem N/A linux-firmware 1.173.9 SourcePackage: linux-oem UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 06/27/2019 dmi.bios.vendor: Dell Inc. dmi.bios.version: 1.12.0 dmi.board.name: 0184M4 dmi.board.vendor: Dell Inc. dmi.board.version: X00 dmi.chassis.type: 10 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvr1.12.0:bd06/27/2019:svnDellInc.:pnPrecision5530:pvr:rvnDellInc.:rn0184M4:rvrX00:cvnDellInc.:ct10:cvr: dmi.product.family: Precision dmi.product.name: Precision 5530 dmi.sys.vendor: Dell Inc. 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