As a workaround you can try booting with "amdgpu.dc=0" Although I don't know if Vega supports disabling DC. With DC disabled, the GPU cannot know if your monitor has been turned off.
Another possible solution is to use an SSH session to try to restore your monitor, typing: DISPLAY=:0.0 xrandr --auto -- 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: Incomplete 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] 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
