I used Linux for quite a while and I never had this problem. My screen blinks every 1.5 second. I tried reinstalling Linux, changing my drivers (tried 495, xserver-xorg-video-nouveau and 460) and switching to integrated intel graphic card via x server settings. I also tried changing GRUB_CMDLINE_LINUX_DEFAULT="nomodeset" to GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" to something else in /etc/default/grub but it just made my gui stop working. It happens on an (almost) clean install. There are some problems in journalctl:
>journalctl -p 0..3
Jan 29 17:13:12 walenty-nitroan51544 kernel: ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PCI0.GPP4.WLAN], AE_NOT_FOUND (20201113/dswload2-162)
Jan 29 17:13:12 walenty-nitroan51544 kernel: ACPI Error: AE_NOT_FOUND, During name lookup/catalog (20201113/psobject-220)
Jan 29 17:13:12 walenty-nitroan51544 kernel: amdgpu 0000:05:00.0: amdgpu: Unsupported power profile mode 0 on RENOIR
Jan 29 17:13:29 walenty-nitroan51544 sddm-helper[1171]: gkr-pam: unable to locate daemon control file
Jan 29 17:13:31 walenty-nitroan51544 kernel: nouveau 0000:01:00.0: can't change power state from D3cold to D0 (config space inaccessible)
Jan 29 17:13:31 walenty-nitroan51544 kernel: nouveau 0000:01:00.0: can't change power state from D3cold to D0 (config space inaccessible)
Jan 29 17:13:31 walenty-nitroan51544 kernel: nouveau 0000:01:00.0: can't change power state from D3cold to D0 (config space inaccessible)
Jan 29 17:13:31 walenty-nitroan51544 kernel: nouveau 0000:01:00.0: tmr: stalled at ffffffffffffffff
This line repeats 20 times.
Those are my specs:
>dpkg -l *nvidia* | grep ii
ii libnvidia-cfg1-470:amd64 470.86-0ubuntu0.20.04.2 amd64 NVIDIA binary OpenGL/GLX configuration library
ii libnvidia-common-470 470.86-0ubuntu0.20.04.2 all Shared files used by the NVIDIA libraries
ii libnvidia-compute-470:amd64 470.86-0ubuntu0.20.04.2 amd64 NVIDIA libcompute package
ii libnvidia-compute-470:i386 470.86-0ubuntu0.20.04.2 i386 NVIDIA libcompute package
ii libnvidia-decode-470:amd64 470.86-0ubuntu0.20.04.2 amd64 NVIDIA Video Decoding runtime libraries
ii libnvidia-decode-470:i386 470.86-0ubuntu0.20.04.2 i386 NVIDIA Video Decoding runtime libraries
ii libnvidia-encode-470:amd64 470.86-0ubuntu0.20.04.2 amd64 NVENC Video Encoding runtime library
ii libnvidia-encode-470:i386 470.86-0ubuntu0.20.04.2 i386 NVENC Video Encoding runtime library
ii libnvidia-extra-470:amd64 470.86-0ubuntu0.20.04.2 amd64 Extra libraries for the NVIDIA driver
ii libnvidia-fbc1-470:amd64 470.86-0ubuntu0.20.04.2 amd64 NVIDIA OpenGL-based Framebuffer Capture runtime library
ii libnvidia-fbc1-470:i386 470.86-0ubuntu0.20.04.2 i386 NVIDIA OpenGL-based Framebuffer Capture runtime library
ii libnvidia-gl-470:amd64 470.86-0ubuntu0.20.04.2 amd64 NVIDIA OpenGL/GLX/EGL/GLES GLVND libraries and Vulkan ICD
ii libnvidia-gl-470:i386 470.86-0ubuntu0.20.04.2 i386 NVIDIA OpenGL/GLX/EGL/GLES GLVND libraries and Vulkan ICD
ii libnvidia-ifr1-470:amd64 470.86-0ubuntu0.20.04.2 amd64 NVIDIA OpenGL-based Inband Frame Readback runtime library
ii libnvidia-ifr1-470:i386 470.86-0ubuntu0.20.04.2 i386 NVIDIA OpenGL-based Inband Frame Readback runtime library
ii linux-modules-nvidia-470-5.13.0-27-generic 5.13.0-27.29~20.04.1 amd64 Linux kernel nvidia modules for version 5.13.0-27
ii linux-modules-nvidia-470-generic-hwe-20.04 5.13.0-27.29~20.04.1 amd64 Extra drivers for nvidia-470 for the generic-hwe-20.04 flavour
ii linux-objects-nvidia-470-5.13.0-27-generic 5.13.0-27.29~20.04.1 amd64 Linux kernel nvidia modules for version 5.13.0-27 (objects)
ii linux-signatures-nvidia-5.13.0-27-generic 5.13.0-27.29~20.04.1 amd64 Linux kernel signatures for nvidia modules for version 5.13.0-27-generic
ii nvidia-compute-utils-470 470.86-0ubuntu0.20.04.2 amd64 NVIDIA compute utilities
ii nvidia-driver-470 470.86-0ubuntu0.20.04.2 amd64 NVIDIA driver metapackage
ii nvidia-kernel-common-470 470.86-0ubuntu0.20.04.2 amd64 Shared files used with the kernel module
ii nvidia-kernel-source-470 470.86-0ubuntu0.20.04.2 amd64 NVIDIA kernel source package
ii nvidia-prime 0.8.16~0.20.04.1 all Tools to enable NVIDIA's Prime
ii nvidia-settings 470.57.01-0ubuntu0.20.04.2 amd64 Tool for configuring the NVIDIA graphics driver
ii nvidia-utils-470 470.86-0ubuntu0.20.04.2 amd64 NVIDIA driver support binaries
ii xserver-xorg-video-nvidia-470 470.86-0ubuntu0.20.04.2 amd64 NVIDIA binary Xorg driver
Also tried using xrandr to set different refresh rate. It seems that rate 144.00 is causing the blinking. I changed the rate a few times back and forth from 144 and 60 and the blinking stopped. However, when I changed to 60 for the first time the blinking got less frequent but much stronger. It's weird.
