AMD APU 上的 Ubuntu 20.04 没有看到最大显示分辨率

Question

突然，Ubuntu 20.04 停止查看最大屏幕分辨率并且仅设置为 1600x900。

我尝试安装从 amd.com 下载的 Ubuntu 驱动程序，但没有帮助。

工作站信息：

$ uname -a
Linux mypc 5.8.0-59-generic #66~20.04.1-Ubuntu SMP Thu Jun 17 11:14:10 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.2 LTS
Release:    20.04
Codename:   focal

$ sudo lshw -C video
  *-display                 
       description: VGA compatible controller
       product: Renoir
       vendor: Advanced Micro Devices, Inc. [AMD/ATI]
       physical id: 0
       bus info: pci@0000:0a:00.0
       version: d8
       width: 64 bits
       clock: 33MHz
       capabilities: pm pciexpress msi msix vga_controller bus_master cap_list rom
       configuration: driver=amdgpu latency=0
       resources: irq:30 memory:d0000000-dfffffff memory:e0000000-e01fffff ioport:e000(size=256) memory:fca00000-fca7ffff memory:c0000-dffff

$ inxi -Gx
Graphics:  Device-1: Advanced Micro Devices [AMD/ATI] Renoir driver: amdgpu v: kernel bus ID: 0a:00.0 
           Display: x11 server: X.Org 1.20.9 driver: amdgpu resolution: 1600x900~60Hz 
           OpenGL: renderer: AMD RENOIR (DRM 3.38.0 5.8.0-59-generic LLVM 11.0.0) v: 4.6 Mesa 20.2.6 direct render: Yes

$ cat ~/.config/monitors.xml 
<monitors version="2">
  <configuration>
    <logicalmonitor>
      <x>0</x>
      <y>0</y>
      <scale>2</scale>
      <primary>yes</primary>
      <monitor>
        <monitorspec>
          <connector>DisplayPort-0</connector>
          <vendor>GSM</vendor>
          <product>LG Ultra HD</product>
          <serial>0x00038da8</serial>
        </monitorspec>
        <mode>
          <width>3840</width>
          <height>2160</height>
          <rate>59.996623992919922</rate>
        </mode>
      </monitor>
    </logicalmonitor>
  </configuration>
</monitors>

记得之前设置过，没想到屏幕分辨率显示不最大，重启也没用。

更新型多巴胺睡眠后分辨率恢复正常。不幸的是我xrandr之前没有捕获输出。目前是

$ xrandr
Screen 0: minimum 320 x 200, current 3840 x 2160, maximum 16384 x 16384
DisplayPort-0 connected primary 3840x2160+0+0 (normal left inverted right x axis y axis) 600mm x 340mm
   3840x2160     60.00*+  30.00  
   2560x1440     59.95  
   1920x1200     60.00  
   1920x1080     60.00    59.94  
   1600x1200     60.00  
   1680x1050     60.00  
   1600x900      60.00  
   1280x1024     60.02  
   1440x900      60.00  
   1280x800      59.81  
   1280x720      60.00    59.94  
   1024x768      60.00  
   800x600       60.32  
   720x480       60.00    59.94  
   640x480       60.00    59.94  
HDMI-A-0 disconnected (normal left inverted right x axis y axis)
HDMI-A-1 disconnected (normal left inverted right x axis y axis)
HDMI-A-2 disconnected (normal left inverted right x axis y axis

现在

$ inxi -Gx
Graphics:  Device-1: Advanced Micro Devices [AMD/ATI] Renoir driver: amdgpu v: kernel bus ID: 0a:00.0 
           Display: x11 server: X.Org 1.20.9 driver: amdgpu resolution: 3840x2160~60Hz 
           OpenGL: renderer: AMD RENOIR (DRM 3.38.0 5.8.0-59-generic LLVM 11.0.0) v: 4.6 Mesa 20.2.6 direct render: Yes

现在的分辨率符合预期分辨率：3840x2160~60Hz