Still occurs on 5.4.0-31 update, only less severe. Laptop is useable now as 
long as no video is being played.
By the looks of it, i915.enable_psr=0 as kernel boot parameter doesn't have any 
notable effect.

The logmessage using drm.debug=0x06 is as follows:

[   84.074499] [drm:drm_mode_addfb2 [drm]] [FB:192]
[   84.090664] [drm:drm_mode_addfb2 [drm]] [FB:220]
[   84.107575] [drm:drm_mode_addfb2 [drm]] [FB:192]
[   84.112742] [drm:i915_hotplug_work_func [i915]] running encoder hotplug 
functions
[   84.112772] [drm:i915_hotplug_work_func [i915]] Connector eDP-1 (pin 4) 
received hotplug event.
[   84.112802] [drm:intel_dp_detect [i915]] [CONNECTOR:191:eDP-1]
[   84.112831] [drm:intel_dp_print_rates [i915]] source rates: 162000, 216000, 
270000, 324000, 432000, 540000
[   84.112857] [drm:intel_dp_print_rates [i915]] sink rates: 162000, 216000, 
243000, 270000, 324000, 378000, 432000, 540000
[   84.112880] [drm:intel_dp_print_rates [i915]] common rates: 162000, 216000, 
270000, 324000, 432000, 540000
[   84.113411] [drm:intel_dp_get_dsc_sink_cap [i915]] DSC DPCD: 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00
[   84.113424] [drm:intel_dp_get_dsc_sink_cap [i915]] FEC CAPABILITY: 0
[   84.113829] [drm:intel_dp_detect [i915]] MST support? port A: no, sink: no, 
modparam: yes
[   84.114226] [drm:drm_dp_get_edid_quirks [drm_kms_helper]] DP sink: EDID mfg 
30-e4 prod-ID 1f-06 quirks: 0x0000
[   84.125822] [drm:drm_mode_addfb2 [drm]] [FB:220]
[   84.142046] [drm:drm_mode_addfb2 [drm]] [FB:192]
[   84.160425] [drm:drm_mode_addfb2 [drm]] [FB:220]

Instead of storms of hotplug events on 5.4.0-29, 5.4.0-31 has single hotplug 
events that cause a single flicker, instead of a storm of hotplug events.
This makes the system almost useable.

In 5.4.0-31 I noticed something else.
Result of dmesg -w | grep vdd_edp
dmesg -w | grep vdd
[  560.948837] [drm:edp_panel_vdd_on [i915]] Turning eDP port A VDD on
[  560.949091] [drm:edp_panel_vdd_on [i915]] PP_STATUS: 0x80000008 PP_CONTROL: 
0x0000006f
[  567.912874] [drm:edp_panel_vdd_off_sync [i915]] Turning eDP port A VDD off
[  567.913095] [drm:edp_panel_vdd_off_sync [i915]] PP_STATUS: 0x80000008 
PP_CONTROL: 0x00000067
[  573.884411] [drm:edp_panel_vdd_on [i915]] Turning eDP port A VDD on
[  573.884594] [drm:edp_panel_vdd_on [i915]] PP_STATUS: 0x80000008 PP_CONTROL: 
0x0000006f
[  580.969230] [drm:edp_panel_vdd_off_sync [i915]] Turning eDP port A VDD off
[  580.969377] [drm:edp_panel_vdd_off_sync [i915]] PP_STATUS: 0x80000008 
PP_CONTROL: 0x00000067
[  590.500251] [drm:edp_panel_vdd_on [i915]] Turning eDP port A VDD on
[  590.500480] [drm:edp_panel_vdd_on [i915]] PP_STATUS: 0x80000008 PP_CONTROL: 
0x0000006f
[  594.537592] [drm:edp_panel_vdd_off_sync [i915]] Turning eDP port A VDD off

It seems that the first that happens when watching a video or doing some
more heavy graphics related stuff for some reason causes the edp panel
to turn on, while it is already on and displaying video for some amounth
of time.

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https://bugs.launchpad.net/bugs/1875649

Title:
  [Ice Lake] Screen flickering in Kubuntu 20.04 on Lenovo Yoga C940
  14-IIL

Status in linux package in Ubuntu:
  Confirmed

Bug description:
  Screen flickering in Kubuntu 20.04 on Lenovo Yoga C940 14-IIL

  I am filing this bug again in accordance with: 
https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1875073/comments/3
  I've deleted the repository and checked again, and the bug still persists.
  Old bug report: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1875073

  My screen flickers on Kubuntu 20.04LTS.
  See: https://imgur.com/a/FoWI1sp

  Also affected:
      Kubuntu 19.10
      Fedora 31

  System:
  inxi -Gxxx
  Graphics:  Device-1: Intel Iris Plus Graphics G7 vendor: Lenovo driver: i915 
v: kernel bus ID: 00:02.0 chip ID: 8086:8a52
             Display: x11 server: X.Org 1.20.8 driver: modesetting compositor: 
kwin_x11 resolution: 1920x1080~60Hz
             OpenGL: renderer: Mesa Intel Iris Plus Graphics (ICL GT2) v: 4.6 
Mesa 20.0.4 direct render: Yes

  Reproduction scenario's:
  1) Starting Kubuntu, screen flickers a couple of times during startup and 
turns black for multiple seconds.
  2) Start a youtube video, near-constant flickering. Audio works fine.
  3) Open up various applications. Screen starts flickering every now and then.
  4) Leave pc unattended for a long time, screen starts flickering sporadically.

  Things I tried:
      * Use various kernels
          * linux kernel 3.4, 3.5, 3.6, 3.7rc2
          * Ubuntu port of linux kernel 3.4.0-26-generic + patch 
https://gitlab.freedesktop.org/jkrzyszt/i915/-/commit/1ee48a61aa57dbdbc3cd2808d8b28df40d938e44
          * intel-drm-next (kernel panic)
          * Oibaf PPA
          * various kernel parameters

  What does work:
      * When using windows, the screen works. So no hardware error.
      * When using "nomodeset" kernel parameter Kubuntu 20.04 works, but then 
there's no sound or hardware acceleration.

  What I think is happening:
      i915 is apperantly an unstable driver for eDP 1.4 screens.
      That, in combination with a 10'th gen intel cpu is not a good combination.
      According to dmesg the firmware of sof-audio-pci is restarting.

          [  324.775087] sof-audio-pci 0000:00:1f.3: error: no reply expected, 
received 0x0
          [  324.866267] sof-audio-pci 0000:00:1f.3: firmware boot complete

      Could the audio part of the eDP connection be breaking because of
  an issue similar to the patch that is mentioned earlyer?

  ProblemType: Bug
  DistroRelease: Ubuntu 20.04
  Package: xorg 1:7.7+19ubuntu14
  ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30
  Uname: Linux 5.4.0-26-generic x86_64
  ApportVersion: 2.20.11-0ubuntu27
  Architecture: amd64
  CasperMD5CheckResult: skip
  CompositorRunning: None
  Date: Tue Apr 28 15:31:27 2020
  DistUpgraded: Fresh install
  DistroCodename: focal
  DistroVariant: ubuntu
  GraphicsCard:
   Intel Corporation Iris Plus Graphics G7 [8086:8a52] (rev 07) (prog-if 00 
[VGA controller])
     Subsystem: Lenovo Iris Plus Graphics G7 [17aa:3801]
  InstallationDate: Installed on 2020-04-25 (3 days ago)
  InstallationMedia: Kubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
  MachineType: LENOVO 81Q9
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.4.0-26-generic 
root=UUID=5d977dfa-1fa5-412b-9d83-644cef18af6e ro rootflags=subvol=@ quiet 
splash vt.handoff=7
  SourcePackage: xorg
  Symptom: display
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 01/09/2020
  dmi.bios.vendor: LENOVO
  dmi.bios.version: AUCN54WW
  dmi.board.asset.tag: NO Asset Tag
  dmi.board.name: LNVNB161216
  dmi.board.vendor: LENOVO
  dmi.board.version: SDK0J40709 WIN
  dmi.chassis.asset.tag: NO Asset Tag
  dmi.chassis.type: 31
  dmi.chassis.vendor: LENOVO
  dmi.chassis.version: Lenovo Yoga C940-14IIL
  dmi.modalias: 
dmi:bvnLENOVO:bvrAUCN54WW:bd01/09/2020:svnLENOVO:pn81Q9:pvrLenovoYogaC940-14IIL:rvnLENOVO:rnLNVNB161216:rvrSDK0J40709WIN:cvnLENOVO:ct31:cvrLenovoYogaC940-14IIL:
  dmi.product.family: Yoga C940-14IIL
  dmi.product.name: 81Q9
  dmi.product.sku: LENOVO_MT_81Q9_BU_idea_FM_Yoga C940-14IIL
  dmi.product.version: Lenovo Yoga C940-14IIL
  dmi.sys.vendor: LENOVO
  version.compiz: compiz N/A
  version.libdrm2: libdrm2 2.4.101-2
  version.libgl1-mesa-dri: libgl1-mesa-dri 20.0.4-2ubuntu1
  version.libgl1-mesa-glx: libgl1-mesa-glx N/A
  version.xserver-xorg-core: xserver-xorg-core 2:1.20.8-2ubuntu2
  version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
  version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-1
  version.xserver-xorg-video-intel: xserver-xorg-video-intel 
2:2.99.917+git20200226-1
  version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1

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