[Bug 1836858] Re: i915: Display flickers (monitor loses signal briefly) during "flickerfree" boot, while showing the BIOS logo on a black background

[Daniel van Vugt]

Interesting. I tried changing this machine to Nvidia-only (nouveau
driver) and the bug remains. So it's not unique to i915.

** Summary changed:

- i915: Display flickers (monitor loses signal briefly) during "flickerfree" boot, while showing the BIOS logo on a black background
+ Display flickers (monitor loses signal briefly) during "flickerfree" boot, while showing the BIOS logo on a black background

** Also affects: plymouth (Ubuntu)
   Importance: Undecided
       Status: New

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Title:
  Display flickers (monitor loses signal briefly) during "flickerfree"
  boot, while showing the BIOS logo on a black background

Status in linux package in Ubuntu:
  Confirmed
Status in plymouth package in Ubuntu:
  New

Bug description:
  I am trying flickerfree boot in 19.10 [1], but find it actually
  flickers part way through:

    1. BIOS logo on a black background.
    2. Display mode resets, no image on a black background briefly.
    3. BIOS logo on a black background.

  The flicker occurs seemingly during kernel startup since my
  peripherals are lit up before the problem occurs.

  Suspecting this might be related to FB handover:

    [    2.751028] fb0: switching to inteldrmfb from EFI VGA

  I tried disabling that with a big hammer:

    i915.modeset=0

  so it stays in efifb, and that works -- no more flickering, providing
  I don't let i915 take over the framebuffer.

  [1] https://discourse.ubuntu.com/t/testing-flickerfree-boot/11854

  ProblemType: Bug
  DistroRelease: Ubuntu 19.10
  Package: linux-image-5.2.0-8-generic 5.2.0-8.9
  ProcVersionSignature: Ubuntu 5.2.0-8.9-generic 5.2.0
  Uname: Linux 5.2.0-8-generic x86_64
  ApportVersion: 2.20.11-0ubuntu5
  Architecture: amd64
  AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/by-path', '/dev/snd/controlC0', '/dev/snd/hwC0D2', '/dev/snd/hwC0D0', '/dev/snd/pcmC0D9p', '/dev/snd/pcmC0D8p', '/dev/snd/pcmC0D7p', '/dev/snd/pcmC0D3p', '/dev/snd/pcmC0D2c', '/dev/snd/pcmC0D0c', '/dev/snd/pcmC0D0p', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
  Date: Wed Jul 17 16:34:36 2019
  InstallationDate: Installed on 2019-05-02 (76 days ago)
  InstallationMedia: Ubuntu 19.10 "Eoan EANIMAL" - Alpha amd64 (20190501)
  MachineType: LENOVO 10M7CTO1WW
  ProcFB: 0 i915drmfb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.2.0-8-generic root=UUID=9bfb5f01-bdd4-4854-bfce-1c28e2f2f3bc ro quiet splash i915.fastboot=1 vt.handoff=7
  PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
  RelatedPackageVersions:
   linux-restricted-modules-5.2.0-8-generic N/A
   linux-backports-modules-5.2.0-8-generic  N/A
   linux-firmware                           1.180
  SourcePackage: linux
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 02/06/2018
  dmi.bios.vendor: LENOVO
  dmi.bios.version: M16KT47A
  dmi.board.name: 3102
  dmi.board.vendor: LENOVO
  dmi.board.version: SDK0J40709 WIN 3259627060530
  dmi.chassis.type: 3
  dmi.chassis.vendor: LENOVO
  dmi.chassis.version: None
  dmi.modalias: dmi:bvnLENOVO:bvrM16KT47A:bd02/06/2018:svnLENOVO:pn10M7CTO1WW:pvrThinkCentreM710s:rvnLENOVO:rn3102:rvrSDK0J40709WIN3259627060530:cvnLENOVO:ct3:cvrNone:
  dmi.product.family: ThinkCentre M710s
  dmi.product.name: 10M7CTO1WW
  dmi.product.sku: LENOVO_MT_10M7_BU_Think_FM_ThinkCentre M710s
  dmi.product.version: ThinkCentre M710s
  dmi.sys.vendor: LENOVO

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