I am having the same issue on my rx570, I am on kernel 5.1.21 -- 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/1790861
Title: amdgpu.dc dual monitor issues when trying to sleep / power off the monitors Status in linux package in Ubuntu: Confirmed Bug description: I have a problem with my dual monitor setup on an AMD RX 580: when I lock the screen and Gnome try to power off both monitors the following happens: 1) the second monitor goes to sleep before the first one, this is normal and expected because the first monitor has a longer time to sleep 2) after some seconds the second monitor turn on back again and prevents the first one to sleep at all 3) gnome detects inactivity on the lock screen for some time and try to power off the monitors again 4) step 1 all over again in an infinite loop When I login back from the lock screen the windows inside my Gnome session can sometimes be rearranged from one screen to the other. After discovering this behavior I tried to power off the monitors manually with `xset dpms force off` and I can confirm that the same happens: the monitors wont really power off because the second one turns back on and prevents the first one to sleep. My guess was that somehow when the second monitor was turning off it delivered some kind of "monitors changed, you should reset" message to the GPU which in order did some kind of "reset everything and power on the monitors back again" action. Searching for a fix to this problem I tried to upgrade my amdgpu mesa drivers using the oibaf/graphics-drivers ppa and after this I tried to upgrade my whole distribution too, moving from bionic to cosmic. Nothing worked. In the end I discovered the existence of amdgpu.dc and tried to disable it with `GRUB_CMDLINE_LINUX_DEFAULT="amdgpu.dc=0"`, this did the trick but it is still a workaround. I'm not sure this is the right place to report this kind of issues but as the issue is somehow critical (the first I entered the power on/off loop I didn't notice it and my monitor cycled power for two hours) I hope this will help other people. --- ProblemType: Bug AlsaVersion: Advanced Linux Sound Architecture Driver Version k4.17.0-9-generic. ApportVersion: 2.20.10-0ubuntu9 Architecture: amd64 Card0.Amixer.info: Card hw:0 'PCH'/'HDA Intel PCH at 0xf7f10000 irq 30' Mixer name : 'Realtek ALC892' Components : 'HDA:10ec0892,104385b0,00100302' Controls : 50 Simple ctrls : 22 Card1.Amixer.info: Card hw:1 'HDMI'/'HDA ATI HDMI at 0xf7e60000 irq 31' Mixer name : 'ATI R6xx HDMI' Components : 'HDA:1002aa01,00aa0100,00100700' Controls : 42 Simple ctrls : 6 CurrentDesktop: GNOME DistroRelease: Ubuntu 18.10 HibernationDevice: RESUME=UUID=7cd1c323-140b-4412-a67a-c46d90a91ff2 InstallationDate: Installed on 2018-09-01 (3 days ago) InstallationMedia: Ubuntu-Server 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725) IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig': 'iwconfig' MachineType: ASUS All Series Package: linux (not installed) ProcFB: 0 amdgpudrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.17.0-9-generic root=UUID=edb6f869-3d1b-4726-bbf1-44b736abfe2b ro amdgpu.dc=0 ProcVersionSignature: Ubuntu 4.17.0-9.10-generic 4.17.17 RelatedPackageVersions: linux-restricted-modules-4.17.0-9-generic N/A linux-backports-modules-4.17.0-9-generic N/A linux-firmware 1.174 RfKill: Error: [Errno 2] No such file or directory: 'rfkill': 'rfkill' Tags: cosmic Uname: Linux 4.17.0-9-generic x86_64 UpgradeStatus: Upgraded to cosmic on 2018-09-04 (0 days ago) UserGroups: adm audio cdrom dip lpadmin lxd plugdev sambashare sudo vboxusers _MarkForUpload: True dmi.bios.date: 08/15/2014 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 2103 dmi.board.asset.tag: To be filled by O.E.M. dmi.board.name: Z87-C 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.:bvr2103:bd08/15/2014:svnASUS:pnAllSeries:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnZ87-C:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion: dmi.product.family: ASUS MB dmi.product.name: All Series dmi.product.version: System Version dmi.sys.vendor: ASUS To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1790861/+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