I'm back to say that kernel 5.4.0-66-generic works for me again after applying the grub default `amdgpu.dc=0` work-around mentioned above.
This is for a Radeon RX 580 if that helps. -- 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/1916919 Title: after upgrade to 5.4.0-66 monitor remains black after off/on cycle Status in linux package in Ubuntu: Confirmed Bug description: i updated today to linux kernel 5.4.0-66-generic. since then the monitor (HDMI) remains black when switched off and on again. this can be corrected once, if a virtual text console hasn't been used so far by switching to a virtual text console and then back to the desktop. Ubuntu 5.4.0-66.74-generic 5.4.86 (Linux Mint 20, Cinnamon 4.6.7) lspci-vnvn.log attached Asrock DeskMini A300 AMD Ryzen 5 2400G with Radeon Vega Graphics × 4 Advanced Micro Devices, Inc. [AMD/ATI] Raven Ridge [Radeon Vega Series / Radeon Vega Mobile Series] --- ProblemType: Bug ApportVersion: 2.20.11-0ubuntu27.16 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC2: kio 1177 F.... pulseaudio /dev/snd/controlC1: kio 1177 F.... pulseaudio /dev/snd/controlC0: kio 1177 F.... pulseaudio CasperMD5CheckResult: skip CurrentDesktop: X-Cinnamon DistroRelease: Linux Mint 20 InstallationDate: Installed on 2020-07-24 (216 days ago) InstallationMedia: Linux Mint 20 "Ulyana" - Release amd64 20200624 IwConfig: lo no wireless extensions. enp3s0 no wireless extensions. MachineType: To Be Filled By O.E.M. To Be Filled By O.E.M. Package: linux (not installed) ProcFB: 0 amdgpudrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-66-generic root=UUID=c96f03d4-1951-4c06-8d5d-61bd5b22b308 ro quiet splash ProcVersionSignature: Ubuntu 5.4.0-66.74-generic 5.4.86 RelatedPackageVersions: linux-restricted-modules-5.4.0-66-generic N/A linux-backports-modules-5.4.0-66-generic N/A linux-firmware 1.187.9 RfKill: Tags: ulyana Uname: Linux 5.4.0-66-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo www-data _MarkForUpload: True dmi.bios.date: 05/15/2019 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: P3.50 dmi.board.name: A300M-STX dmi.board.vendor: ASRock dmi.chassis.asset.tag: To Be Filled By O.E.M. dmi.chassis.type: 3 dmi.chassis.vendor: To Be Filled By O.E.M. dmi.chassis.version: To Be Filled By O.E.M. dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP3.50:bd05/15/2019:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnA300M-STX:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.: dmi.product.family: To Be Filled By O.E.M. dmi.product.name: To Be Filled By O.E.M. dmi.product.sku: To Be Filled By O.E.M. dmi.product.version: To Be Filled By O.E.M. dmi.sys.vendor: To Be Filled By O.E.M. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1916919/+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
