Thanks for the animation.

I think that flicker is occurring in the LCD itself. The reason is that
the old gradient (which was only used in Ubuntu 18.10) covers more
colours than 24-bit RGB can support. On top of that, if your monitor is
only 18-bit RGB in hardware then you will see even fewer colours and the
display/kernel will flicker on purpose to create the illusion of all the
shades it can't really display. This is called temporal dithering, or
Frame Rate Control:

Essentially that gradient is just a pathological case which will make
the shimmering/flickering more visible than it usually is. For this and
other reasons, I reported a bug 1789355 too.

In the end this is a hardware limitation. But it is a common one which
the kernel driver should have some control over. You should be able to
configure the nouveau kernel driver directly using something like:

  xrandr --output DVI-I-1 --set "dithering mode" "off"


  xrandr --output DVI-I-1 --set "dithering mode" "static 2x2"

based on your Xrandr.txt which says:

        dithering depth: auto 
                supported: auto, 6 bpc, 8 bpc
        dithering mode: auto 
                supported: auto, off, static 2x2, dynamic 2x2

I am going to reassign this bug to the kernel because it sounds like the
only software solution possible here would be for the kernel to
automatically choose a less annoying dithering mode for this model of

P.S. The gradient is completely gone in Ubuntu 19.04 so you won't have
any trouble there.

** Package changed: xorg-server (Ubuntu) => linux (Ubuntu)

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  [nouveau] Scrolling screen flicker, especially on default Ubuntu lock

Status in linux package in Ubuntu:

Bug description:
  My screen is experiencing a weird "scrolling" flicker, especially
  while displaying blue, indigo, and violet hues/colors, such as on the
  default Ubuntu 18.10 (x64 Desktop) lock screen. The screen flicker
  scrolls up and down, with the brightest part of the flicker being
  towards the top, with a gradient that fades back to the original color
  near the bottom.

  Problem occurs on any one monitor on any one video output protocol
  (DVI-D, HDMI, and VGA).

  I will upload an illustration or render as soon as possible for better 

  ProblemType: Bug
  DistroRelease: Ubuntu 18.10
  Package: xorg 1:7.7+19ubuntu8
  ProcVersionSignature: Ubuntu 4.18.0-16.17-generic 4.18.20
  Uname: Linux 4.18.0-16-generic x86_64
  ApportVersion: 2.20.10-0ubuntu13.2
  Architecture: amd64
  BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
  CompositorRunning: None
  CurrentDesktop: ubuntu:GNOME
  Date: Thu Mar  7 10:39:50 2019
  DistUpgraded: 2018-10-19 10:50:54,557 ERROR got error from PostInstallScript 
./ (g-exec-error-quark: Failed to execute child process 
“./” (No such file or directory) (8))
  DistroCodename: cosmic
  DistroVariant: ubuntu
  ExtraDebuggingInterest: Yes, if not too technical
   NVIDIA Corporation GF108 [GeForce GT 440] [10de:0de0] (rev a1) (prog-if 00 
[VGA controller])
     Subsystem: NVIDIA Corporation GF108 [GeForce GT 440] [10de:0828]
  InstallationDate: Installed on 2018-08-17 (202 days ago)
  InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
  MachineType: BIOSTAR Group A880G+
   PATH=(custom, no user)
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.18.0-16-generic 
root=UUID=a967adb1-1600-455b-8704-e2bf5de5081d ro quiet splash vt.handoff=1
  SourcePackage: xorg
  UpgradeStatus: Upgraded to cosmic on 2018-10-19 (139 days ago) 09/21/2011
  dmi.bios.vendor: American Megatrends Inc.
  dmi.bios.version: 080016
  dmi.board.asset.tag: To Be Filled By O.E.M. A880G+
  dmi.board.vendor: BIOSTAR Group
  dmi.chassis.asset.tag: None
  dmi.chassis.type: 3
  dmi.chassis.vendor: BIOSTAR Group
dmi:bvnAmericanMegatrendsInc.:bvr080016:bd09/21/2011:svnBIOSTARGroup:pnA880G+:pvr:rvnBIOSTARGroup:rnA880G+:rvr:cvnBIOSTARGroup:ct3:cvr: To Be Filled By O.E.M. A880G+
  dmi.product.sku: To Be Filled By O.E.M.
  dmi.sys.vendor: BIOSTAR Group
  version.compiz: compiz N/A
  version.libdrm2: libdrm2 2.4.95-1
  version.libgl1-mesa-dri: libgl1-mesa-dri 18.2.2-0ubuntu1
  version.libgl1-mesa-glx: libgl1-mesa-glx 18.2.2-0ubuntu1
  version.xserver-xorg-core: xserver-xorg-core 2:1.20.1-3ubuntu2.1
  version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
  version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:18.1.0-1
  version.xserver-xorg-video-intel: xserver-xorg-video-intel 
  version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-3

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