Black Screen After Changing Screen Resolution on Ubuntu 19.04

Question

I have a laptop with AMD Ryzen 2500u, Vega 8 graphics card. I installed Ubuntu 19.04 with GNOME. But my issue is that I can't change the screen resolution from my current (1920x1080) to any other one, or I'll get a black screen.

This is the output of xrandr:

Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
   1920x1080     60.01*+  60.01    59.97    59.96    59.93    47.10  
   1680x1050     60.01    59.95    59.88  
   1600x1024     60.17  
   1400x1050     59.98  
   1600x900      59.99    59.94    59.95    59.82  
   1280x1024     60.01    60.02  
   1440x900      60.01    59.89  
   1400x900      59.96    59.88  
   1280x960      60.00  
   1440x810      60.00    59.97  
   1368x768      59.88    59.85  
   1360x768      59.80    59.96  
   1280x800      59.99    60.01    59.97    59.81    59.91  
   1152x864      60.00  
   1280x720      60.00    60.01    59.99    59.86    59.74  
   1024x768      60.01    60.04    60.00  
   960x720       60.00  
   928x696       60.05  
   896x672       60.01  
   1024x576      59.95    59.96    59.90    59.82  
   960x600       59.93    60.00  
   960x540       59.96    59.99    59.63    59.82  
   800x600       60.01    60.00    60.32    56.25  
   840x525       60.01    59.88  
   864x486       59.92    59.57  
   800x512       60.17  
   700x525       59.98  
   800x450       59.95    59.82  
   640x512       60.02  
   720x450       59.89  
   700x450       59.96    59.88  
   640x480       60.01    60.00    59.94  
   720x405       59.51    58.99  
   684x384       59.88    59.85  
   680x384       59.80    59.96  
   640x400       59.88    59.98  
   576x432       60.06  
   640x360       59.86    59.83    59.84    59.32  
   512x384       60.00  
   512x288       60.00    59.92  
   480x270       59.63    59.82  
   400x300       60.32    56.34  
   432x243       59.92    59.57  
   320x240       60.05  
   360x202       59.51    59.13  
   320x180       59.84    59.32 

I tried other desktop environments such as Xfce/Cinnamon.. But no luck.

Any help?

Answer 1

I had this issue too (or an issue very similar to this) on my new T495 although I can't say for sure whether my solution will work on Ubuntu as I am using Fedora 31 KDE.

By default it seems to use the amdgpu driver built into the kernel and then when X is started it uses the modesetting xorg driver. To rectify the issue, I instead used the amdgpu DDX driver for xorg. On Fedora, the package for this is xorg-x11-drv-amdgpu. As I don't use Ubuntu I'm not 100% sure what the package is on that (a quick google suggests xserver-xorg-video-amdgpu). My xrandr output looked much like yours before with the modesetting driver, now though (with the DDX driver) it looks like this:

Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
eDP connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 309mm x 173mm
   1920x1080     60.00*+
   1680x1050     60.00  
   1280x1024     60.00  
   1440x900      60.00  
   1280x800      60.00  
   1280x720      60.00  
   1024x768      60.00  
   800x600       60.00  
   640x480       60.00  
HDMI-A-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 disconnected (normal left inverted right x axis y axis)

As a side note, I was also unable to recover from suspending when using the (default) modesetting driver and the only way to recover was to reset the machine. On reboot there was an error in the logs referencing dcn10_hw_sequencer.c, however using the DDX driver, I am now able to recover from suspending the machine successfully.