This issue appears to be an upstream bug, since you tested the latest upstream kernel. Would it be possible for you to open an upstream bug report[0]? That will allow the upstream Developers to examine the issue, and may provide a quicker resolution to the bug.
Please follow the instructions on the wiki page[0]. The first step is to email the appropriate mailing list. If no response is received, then a bug may be opened on bugzilla.kernel.org. Once this bug is reported upstream, please add the tag: 'kernel-bug- reported-upstream'. [0] https://wiki.ubuntu.com/Bugs/Upstream/kernel ** Changed in: linux (Ubuntu) Importance: Undecided => High ** Changed in: linux (Ubuntu) Status: Confirmed => Triaged ** Also affects: linux (Ubuntu Cosmic) Importance: High Status: Triaged ** Also affects: linux (Ubuntu Bionic) Importance: Undecided Status: New ** Changed in: linux (Ubuntu Bionic) Status: New => Triaged ** Changed in: linux (Ubuntu Bionic) Importance: Undecided => High ** Tags added: kernel-da-key -- 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/1784156 Title: [regression][amdgpu] analog output stops working on R9 380/Tonga Pro after upgrading to Ubuntu 18.04 Status in linux package in Ubuntu: Triaged Status in linux source package in Bionic: Triaged Status in linux source package in Cosmic: Triaged Bug description: After upgrading to Ubuntu 18.04 (and thus from Linux 4.13 to Linux 4.15) the Monitor connected via VGA (through DVI-I) shows a 'No Signal' message after amdgpu takes over from efifb and turns off. The monitor worked fine in Ubuntu 17.10 and Linux 4.13. When looking at the output of xrandr, the analog monitor is now detected as DVI-D instead of DVI-I and thus probably won't receive an analog signal anymore. After some investigation, it turns out the monitor will light up when adding the `amdgpu.dc=0` kernel parameter. I've tried Linux 4.18-rc6 from the mainline ppa and the issue persists unless I add the kernel parameter to disable DC. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-generic 4.15.0.29.31 ProcVersionSignature: Ubuntu 4.15.0-29.31-generic 4.15.18 Uname: Linux 4.15.0-29-generic x86_64 ApportVersion: 2.20.9-0ubuntu7.2 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/pcmC0D0p: benpicco 2151 F...m pulseaudio /dev/snd/controlC0: benpicco 2151 F.... pulseaudio /dev/snd/controlC1: benpicco 2151 F.... pulseaudio CurrentDesktop: MATE Date: Sat Jul 28 17:55:35 2018 EcryptfsInUse: Yes HibernationDevice: RESUME=UUID=ef400a46-b237-4272-b4a7-f866e92d00a0 InstallationDate: Installed on 2016-08-06 (720 days ago) InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719) IwConfig: lo no wireless extensions. eno1 no wireless extensions. MachineType: System manufacturer System Product Name ProcFB: 0 amdgpudrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-29-generic root=UUID=8e6b0d6a-eb87-44cf-8fc3-b13bd97b71d2 ro amdgpu.dc=0 RelatedPackageVersions: linux-restricted-modules-4.15.0-29-generic N/A linux-backports-modules-4.15.0-29-generic N/A linux-firmware 1.173.1 RfKill: 0: hci0: Bluetooth Soft blocked: no Hard blocked: no SourcePackage: linux UpgradeStatus: Upgraded to bionic on 2018-07-28 (0 days ago) dmi.bios.date: 11/09/2012 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 3603 dmi.board.asset.tag: To be filled by O.E.M. dmi.board.name: P8Z68-V 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.:bvr3603:bd11/09/2012:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnP8Z68-V: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/1784156/+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
