[Bug 1711452] Re: grub.cfg falls back to 'text' video mode on UEFI which is not supported

[Steve Langasek]

Junien, no, this can't be worked around with a kernel boot option.

Are you experiencing this when booting via MAAS?  MAAS does its own
grub.cfg management, and would need to be fixed separately for this
issue.

You can work around this in the grub.cfg on a given installed system by
running:

  sudo sed -i -e'/linux_gfx_mode/s/text/auto/' /etc/grub.d/10_linux &&
sudo update-grub

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https://bugs.launchpad.net/bugs/1711452

Title:
  grub.cfg falls back to 'text' video mode on UEFI which is not
  supported

Status in grub2 package in Ubuntu:
  Triaged

Bug description:
  The grub.cfg generated by update-grub for both UEFI and BIOS includes
  the following logic:

  ### BEGIN /etc/grub.d/10_linux ###
  function gfxmode {
          set gfxpayload="${1}"
          if [ "${1}" = "keep" ]; then
                  set vt_handoff=vt.handoff=7
          else
                  set vt_handoff=
          fi
  }
  if [ "${recordfail}" != 1 ]; then
    if [ -e ${prefix}/gfxblacklist.txt ]; then
      if hwmatch ${prefix}/gfxblacklist.txt 3; then
        if [ ${match} = 0 ]; then
          set linux_gfx_mode=keep
        else
          set linux_gfx_mode=text
        fi
      else
        set linux_gfx_mode=text
      fi
    else
      set linux_gfx_mode=keep
    fi
  else
    set linux_gfx_mode=text
  fi
  export linux_gfx_mode

  [...]

  menuentry [...]
      gfxmode $linux_gfx_mode

  This means that in some cases, we are calling 'set gfxpayload="text"'
  on UEFI systems.

  However, grub-core/loader/i386/linux.c has:

  #ifdef GRUB_MACHINE_EFI
  #include <grub/efi/efi.h>
  #define HAS_VGA_TEXT 0
  #define DEFAULT_VIDEO_MODE "auto"
  #define ACCEPTS_PURE_TEXT 0
  #elif [...]

  and if ACCEPTS_PURE_TEXT is 0, grub_linux_boot() masks
  GRUB_VIDEO_MODE_TYPE_PURE_TEXT out of the allowed set when calling
  grub_video_set_mode().

  So our generated grub.cfg should *never* be setting gfxpayload=text on
  a UEFI system.  If we do, we get the following error message from grub
  at boot:

  error: invalid video mode specification `text'.
  Booting in blind mode

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