[Bug 1828273] Re: Framebuffer setting in GRUB_CMDLINE_LINUX_DEFAULT has no effect

[John Bester]

I found another comment online and tried it: I added "blacklist efifb"
to /etc/modprobe.d/blacklist-framebuffer.conf. I then executed "update-
initramfs -u" followed by "update-grub" and rebooted. Still no joy.

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Title:
  Framebuffer setting in GRUB_CMDLINE_LINUX_DEFAULT has no effect

Status in grub2 package in Ubuntu:
  New

Bug description:
  I have an Ubuntu Server 18.04 installation with KVM and a guest OS to
  which a AMD video card needs to be passed through. It worked great for
  about 9 months and after a recent Ubuntu upgrade, efifb grabs the
  video card irrespective of the linux command line. The commnand line
  that worked before is:

  GRUB_CMDLINE_LINUX_DEFAULT="amd_iommu=on iommu=pt pci_stubs=1106:3483
  vga=normal nofb nomodeset video=efifb:off"

  Currently, this is the command line (changes I made based on searching the web for hours):
  GRUB_CMDLINE_LINUX_DEFAULT="quiet amd_iommu=on iommu=pt earlymodules=vfio-pci pci_stubs=1106:3483 vga=normal nofb nomodeset video=vesafb:off,efifb:off gfxpayload=text"

  The current active kernel options (proc/cmdline)

  BOOT_IMAGE=/boot/vmlinuz-4.15.0-48-generic
  root=UUID=a83137ad-9598-4dc2-aca9-7ab19d17d3c0 ro quiet amd_iommu=on
  iommu=pt earlymodules=vfio-pci pci_stubs=1106:3483 vga=normal nofb
  nomodeset video=vesafb:on,efifb:off gfxpayload=text

  This is verified by syslog:

  [    0.000000] Command line:
  BOOT_IMAGE=/boot/vmlinuz-4.15.0-48-generic
  root=UUID=a83137ad-9598-4dc2-aca9-7ab19d17d3c0 ro quiet amd_iommu=on
  iommu=pt earlymodules=vfio-pci pci_stubs=1106:3483 vga=normal nofb
  nomodeset video=vesafb:on,efifb:off gfxpayload=text

  According to one of the web sites I found, any (or all) of the
  following options should disable the frame buffer:

  vga=normal nofb nomodeset video=vesafb:on,efifb:off

  Yet, a framebuffer is still created

  crw-rw---- 1 root video 29, 0 May  8 18:26 /dev/fb0

  Memory locked by efifb (grep -B 5 -A 5 "26[:]00" /proc/iomem)

  e0000000-fec2ffff : PCI Bus 0000:00
    e0000000-f01fffff : PCI Bus 0000:26
      e0000000-efffffff : 0000:26:00.0
        e0000000-e01effff : efifb
      f0000000-f01fffff : 0000:26:00.0
        f0000000-f01fffff : vfio-pci

  Yet, vfio driver is successfully loaded for this device: (ls
  /sys/bus/pci/drivers/vfio-pci/)

  /sys/bus/pci/drivers/vfio-pci/0000:26:00.0
  /sys/bus/pci/drivers/vfio-pci/0000:26:00.1

  Any help on how efifb can be blocked from loading will be greatly
  appreciated.

  ProblemType: Bug
  DistroRelease: Ubuntu 18.04
  Package: grub2-common 2.02-2ubuntu8.13
  ProcVersionSignature: Ubuntu 4.15.0-47.50-generic 4.15.18
  Uname: Linux 4.15.0-47-generic x86_64
  ApportVersion: 2.20.9-0ubuntu7.6
  Architecture: amd64
  CurrentDesktop: GNOME
  Date: Wed May  8 19:32:36 2019
  InstallationDate: Installed on 2017-01-12 (846 days ago)
  InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
  SourcePackage: grub2
  UpgradeStatus: Upgraded to bionic on 2018-09-27 (223 days ago)

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