Some details on the lightdm/lockscreen issue. I just noticed that if I switch to tty1 and go back to lightdm everything is displayed properly, or well, that's what I thought at first, because when I tried to click something or even type, it was unresponsive, it's like a frozen frame, basically, like a lightdm's screenshot. I could still notice the cursor responding to text areas, so I could as well login successfully since lightdm is actually running.
From my deeply ignorant point of view, that 'black screen' at the beginning it's more like the last 'frame' from the booting process, after that, it never refreshes and appears to be pure blackness. If I go tty mode, and go back to lightdm it refreshes graphically for a second, but still, no animations at all, no text, no menus, nothing, like clicking/typing on a picture, except for the cursor which seems to be working correctly. This is from journalctl, every time I go from lightdm/cinnamon's lockscreen to tty and vice versa. #tty1 14 00:10:31 debian kernel: [drm] PCIE GART of 256M enabled (table at 0x000000F400000000). 14 00:10:31 debian kernel: [drm] UVD and UVD ENC initialized successfully. 14 00:10:31 debian kernel: [drm] VCE initialized successfully. 14 00:10:38 debian kernel: amdgpu 0000:03:00.0: GPU pci config reset #back to lockscreen (lightdm gives the same output) 14 00:11:03 debian kernel: [drm] PCIE GART of 256M enabled (table at 0x000000F400000000). 14 00:11:03 debian kernel: [drm] UVD and UVD ENC initialized successfully. 14 00:11:03 debian kernel: [drm] VCE initialized successfully. 14 00:11:10 debian kernel: amdgpu 0000:03:00.0: GPU pci config reset
