I have found a fix. First I tried adding "nouveau.modeset=0" to bootflags, which got me to boot but no greeter. sddm appeared to be happily running but it failed to start the display server restarting it did not help "startx" worked, which gave me hope
It appeared the session "seat" had been determined by systemd to have "CanGraphical" false Then I found this: https://github.com/mikhailnov/systemd/commit/c00bf275fdfbad3a9db8934b5e266b6abbdb8443 There's a heuristic hack which sets CanGraphical when the kernel starts w/o graphics, but only if this is done via "nomodeset" rather than the driver-specific ".modeset" flags So I just added "nomodeset" to boot flags, and now not only does 6.5.0-28 boot and land at a working greeter again, but all the weird sddm graphics bugs i'd been encountering since 6.5 are gone. Hope this helps someone else... And maybe this kernel issue will get fixed, some day -- 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/1788044 Title: task kworker blocked for more than 120 seconds nouveau Status in linux package in Ubuntu: Incomplete Status in xserver-xorg-video-nouveau package in Ubuntu: Confirmed Bug description: I was using chromium when the whole system GUI stopped responding at 15:42. This corresponds to the system journal at that point: Aug 20 15:42:56 dh3930 kernel: nouveau 0000:01:00.0: fifo: SCHED_ERROR 0a [CTXSW_TIMEOUT] Aug 20 15:42:56 dh3930 kernel: nouveau 0000:01:00.0: fifo: runlist 0: scheduled for recovery Aug 20 15:42:56 dh3930 kernel: nouveau 0000:01:00.0: fifo: channel 15: killed Aug 20 15:42:56 dh3930 kernel: nouveau 0000:01:00.0: fifo: engine 0: scheduled for recovery Aug 20 15:42:56 dh3930 kernel: nouveau 0000:01:00.0: compiz[7682]: channel 15 killed! Aug 20 15:45:50 dh3930 kernel: INFO: task kworker/u24:4:14623 blocked for more than 120 seconds. Aug 20 15:45:50 dh3930 kernel: Not tainted 4.15.0-32-generic #35-Ubuntu Aug 20 15:45:50 dh3930 kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Aug 20 15:45:50 dh3930 kernel: kworker/u24:4 D 0 14623 2 0x80000000 Aug 20 15:45:50 dh3930 kernel: Workqueue: events_unbound nv50_disp_atomic_commit_work [nouveau] Aug 20 15:45:50 dh3930 kernel: Call Trace: Aug 20 15:45:50 dh3930 kernel: __schedule+0x291/0x8a0 Aug 20 15:45:50 dh3930 kernel: schedule+0x2c/0x80 Aug 20 15:45:50 dh3930 kernel: schedule_timeout+0x1cf/0x350 Aug 20 15:45:50 dh3930 kernel: ? nvif_object_ioctl+0x47/0x50 [nouveau] Aug 20 15:45:50 dh3930 kernel: ? nouveau_bo_rd32+0x2a/0x30 [nouveau] Aug 20 15:45:50 dh3930 kernel: ? nv84_fence_read+0x2e/0x30 [nouveau] Aug 20 15:45:50 dh3930 kernel: ? nouveau_fence_no_signaling+0x2a/0x80 [nouveau] Aug 20 15:45:50 dh3930 kernel: dma_fence_default_wait+0x1c7/0x260 Aug 20 15:45:50 dh3930 kernel: ? dma_fence_release+0xa0/0xa0 Aug 20 15:45:50 dh3930 kernel: dma_fence_wait_timeout+0x3e/0xf0 Aug 20 15:45:50 dh3930 kernel: drm_atomic_helper_wait_for_fences+0x63/0xc0 [drm_kms_helper] Aug 20 15:45:50 dh3930 kernel: nv50_disp_atomic_commit_tail+0x55/0x3b10 [nouveau] Aug 20 15:45:50 dh3930 kernel: nv50_disp_atomic_commit_work+0x12/0x20 [nouveau] Aug 20 15:45:50 dh3930 kernel: process_one_work+0x1de/0x410 Aug 20 15:45:50 dh3930 kernel: worker_thread+0x32/0x410 Aug 20 15:45:50 dh3930 kernel: kthread+0x121/0x140 Aug 20 15:45:50 dh3930 kernel: ? process_one_work+0x410/0x410 Aug 20 15:45:50 dh3930 kernel: ? kthread_create_worker_on_cpu+0x70/0x70 Aug 20 15:45:50 dh3930 kernel: ret_from_fork+0x35/0x40 The 'blocked for more than 120 seconds' message and call trace repeated every ~121 seconds until I rebooted. At that point, the following additional line appeared with the 'blocked for more than 120 seconds' message: Aug 20 16:01:51 dh3930 kernel: nouveau 0000:01:00.0: chromium- browse[14187]: failed to idle channel 20 [chromium-browse[14187]] ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.15.0-32-generic 4.15.0-32.35 ProcVersionSignature: Ubuntu 4.15.0-32.35-generic 4.15.18 Uname: Linux 4.15.0-32-generic x86_64 ApportVersion: 2.20.9-0ubuntu7.2 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: david 2460 F.... pulseaudio /dev/snd/controlC0: david 2460 F.... pulseaudio CurrentDesktop: Unity:Unity7:ubuntu Date: Mon Aug 20 16:07:40 2018 EcryptfsInUse: Yes HibernationDevice: RESUME=UUID=9e4f3d6a-f1b3-40c0-8c97-97d861a7ce11 InstallationDate: Installed on 2016-10-24 (664 days ago) InstallationMedia: Ubuntu 16.10 "Yakkety Yak" - Release amd64 (20161012.2) MachineType: System manufacturer System Product Name ProcFB: 0 nouveaufb ProcKernelCmdLine: BOOT_IMAGE=/@/boot/vmlinuz-4.15.0-32-generic root=UUID=311cc681-166d-47bd-847d-f41c81578c1a ro rootflags=subvol=@ quiet splash vt.handoff=1 RelatedPackageVersions: linux-restricted-modules-4.15.0-32-generic N/A linux-backports-modules-4.15.0-32-generic N/A linux-firmware 1.173.1 RfKill: SourcePackage: linux UpgradeStatus: Upgraded to bionic on 2018-05-01 (110 days ago) dmi.bios.date: 05/06/2014 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 4701 dmi.board.asset.tag: To be filled by O.E.M. dmi.board.name: P9X79 dmi.board.vendor: ASUSTeK COMPUTER INC. dmi.board.version: Rev 1.xx dmi.chassis.asset.tag: Asset-1234567890 dmi.chassis.type: 3 dmi.chassis.vendor: Chassis Manufacture dmi.chassis.version: Chassis Version dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr4701:bd05/06/2014:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnP9X79:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion: dmi.product.family: To be filled by O.E.M. dmi.product.name: System Product Name dmi.product.version: System Version dmi.sys.vendor: System manufacturer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1788044/+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
