Fractional scaling problems with apps display

hi there,
I have two monitors 4k 27" and HD 24" so I did set up a fractional scaling. Since the I noticed few issues. The VirtualBox app doesn't display any GUI elements inside the main window.

VLC doesn't display any video but I can hear audio.

The default video app does display everything correctly as long as it's not in full screen mode. When I go to full screen mode the app is moved into my second screen and resolution/scaling is changed.

All the problems are gone when I turn off fractional scaling.

System:    Host: l080-PC Kernel: 5.11.0-34-generic x86_64 bits: 64 compiler: N/A 
           Desktop: Gnome 3.38.4 Distro: Zorin OS 16 base: Ubuntu 20.04 LTS Focal 
Machine:   Type: Desktop Mobo: Micro-Star model: Z490-A PRO (MS-7C75) v: 1.0 
           serial: <superuser/root required> UEFI: American Megatrends v: 2.90 date: 04/20/2021 
CPU:       Topology: 10-Core model: Intel Core i9-10850K bits: 64 type: MT MCP arch: N/A 
           L2 cache: 20.0 MiB 
           flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 144000 
           Speed: 896 MHz min/max: 800/5200 MHz Core speeds (MHz): 1: 931 2: 4514 3: 3356 
           4: 2042 5: 1384 6: 1121 7: 800 8: 800 9: 800 10: 800 11: 800 12: 800 13: 800 14: 800 
           15: 800 16: 800 17: 800 18: 2249 19: 3769 20: 2441 
Graphics:  Device-1: AMD Ellesmere [Radeon RX 470/480/570/570X/580/580X/590] 
           vendor: Sapphire Limited Nitro+ driver: amdgpu v: kernel bus ID: 01:00.0 
           Display: x11 server: X.Org 1.20.11 driver: amdgpu 
           resolution: 1920x1080~60Hz, 3840x2160~60Hz 
           renderer: Radeon RX 580 Series (POLARIS10 DRM 3.40.0 5.11.0-34-generic LLVM 12.0.1) 
           v: 4.6 Mesa 21.3.0-devel (git-fb5deb2 2021-09-10 focal-oibaf-ppa) direct render: Yes 
Audio:     Device-1: Intel Comet Lake PCH cAVS vendor: Micro-Star MSI driver: snd_hda_intel 
           v: kernel bus ID: 00:1f.3 
           Device-2: AMD Ellesmere HDMI Audio [Radeon RX 470/480 / 570/580/590] 
           vendor: Sapphire Limited driver: snd_hda_intel v: kernel bus ID: 01:00.1 
           Device-3: Corsair type: USB driver: hid-generic,snd-usb-audio,usbhid bus ID: 1-1.4:11 
           Sound Server: ALSA v: k5.11.0-34-generic 
Network:   Device-1: Realtek RTL8125 2.5GbE vendor: Micro-Star MSI driver: r8169 v: kernel 
           port: 3000 bus ID: 04:00.0 
           IF: enp4s0 state: down mac: d8:bb:c1:11:2a:46 
           Device-2: Intel Wireless 8260 driver: iwlwifi v: kernel port: 3000 bus ID: 05:00.0 
           IF: wlp5s0 state: up mac: f4:8c:50:42:67:79 
Drives:    Local Storage: total: 4.55 TiB used: 383.88 GiB (8.2%) 
           ID-1: /dev/nvme0n1 vendor: Crucial model: CT500P2SSD8 size: 465.76 GiB 
           ID-2: /dev/nvme1n1 vendor: Samsung model: SSD 980 PRO 1TB size: 931.51 GiB 
           ID-3: /dev/sda vendor: Seagate model: ST2000DM008-2FR102 size: 1.82 TiB 
           ID-4: /dev/sdb vendor: Crucial model: CT2000MX500SSD1 size: 1.82 TiB 
Partition: ID-1: / size: 227.98 GiB used: 62.95 GiB (27.6%) fs: ext4 dev: /dev/nvme0n1p2 
Sensors:   System Temperatures: cpu: 52.0 C mobo: N/A gpu: amdgpu temp: 47 C 
           Fan Speeds (RPM): N/A gpu: amdgpu fan: 763 
Info:      Processes: 414 Uptime: 22h 20m Memory: 31.28 GiB used: 5.21 GiB (16.7%) Init: systemd 
           runlevel: 5 Compilers: gcc: 9.3.0 Shell: bash v: 5.0.17 inxi: 3.0.38 

Thanks for any help :slight_smile:

I'm running POP OS at the moment (until I get Zorin to install). However, I also have a 4K monitor and scaling generally and fractional scaling specifically (in POP OS) have been a problem for me.

What I've done is disable fractional scaling and use Gnome Tweaks to scale the font size. Generally this works, but some apps don't space properly for increased font size (Audacity for example).

In the live demo of Zorin, I tried increasing the font sizes from its settings panel (not using Gnome Tweaks). This seemed to work surprisingly well. I would try this first.


as I'm using two screens HD and 4k changing the font size was not the perfect solution as on my HD screen everything was supper large. I found the solution to my problem here

So I disabled all scaling and I'm running a following script on the system startup.

xrandr --fbmm 6720x3780 --output HDMI-A-0 --pos 2880x0 --mode 3840x2160 --scale 1x1 --primary --output HDMI-A-1 --pos 0x270 --mode 1920x1080 --scale 1.5x1.5

Above command fixed my scaling problem but it created new problem with cursor.

Cursor flickers with xrandr scaling

so now my script looks like:

xrandr --fbmm 6720x3780 --output HDMI-A-0 --pos 2880x0 --mode 3840x2160 --scale 0.9999x0.9999 --primary --output HDMI-A-1 --pos 0x0 --mode 1920x1080 --scale 1.5x1.5

Thanks. I'll check this out.

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