After grepping dmesg for all lines about the "00:15" devices, I found two lines starting with "DMAR:", which made me think of another machine running debian which had issues with DMAR: devices that were related to the Intel IOMMU.
So I tried the workaround I knew from there: Edit /etc/default/grub and add "intel_iommu=off" to the GRUB_CMDLINE_LINUX_DEFAULT value, then run "sudo update-grub" to update the grub configuration and reboot. and voila, intel-lpss initializes within a few milliseconds again: [ 6.518592] intel-lpss 0000:00:15.0: enabling device (0000 -> 0002) [ 6.560693] idma64 idma64.0: Found Intel integrated DMA 64-bit [ 6.569509] intel-lpss 0000:00:15.1: enabling device (0000 -> 0002) [ 6.569691] idma64 idma64.1: Found Intel integrated DMA 64-bit [ 6.574164] mei_me 0000:00:16.0: enabling device (0000 -> 0002) $ cat /proc/cmdline BOOT_IMAGE=/boot/vmlinuz-4.15.0-177-generic root=UUID=<blabla> ro intel_iommu=off So some change between 4.15.0-176 and 4.15.0-177 seemingly broke the Intel IOMMU. Question is whether it was a formerly "dormant" BIOS bug that was only unveiled by some change, or whether it is a newly introduced Linux bug that broke Intel IOMMU support... -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1973167 Title: linux-image-4.15.0-177-generic freezes on the welcome screen To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1973167/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
