have really quick '_' on boot before first purple screen

Bug #861048 reported by Jason Warner on 2011-09-28
This bug affects 5 people
Affects Status Importance Assigned to Milestone
The Ubuntu Flicker-Free Boot Project
grub2 (Ubuntu)
Colin Watson
Colin Watson

Bug Description

Hoping to get an entirely TFB (text-free boot) and FFB (flicker-free boot), I see a '_' on a black screen just after my bios. This is before I see my first purple screen.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: grub2 (not installed)
ProcVersionSignature: Ubuntu 3.0.0-12.19-generic 3.0.4
Uname: Linux 3.0.0-12-generic x86_64
ApportVersion: 1.23-0ubuntu1
Architecture: amd64
Date: Wed Sep 28 10:16:24 2011
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110919)
 PATH=(custom, user)
SourcePackage: grub2
UpgradeStatus: No upgrade log present (probably fresh install)

Brian Murray (brian-murray) wrote :

I see a quickly blinking '_' right before by grub menu using Ubuntu 11.10 so I am setting this bug report to Triaged.

Changed in grub2 (Ubuntu):
status: New → Triaged
importance: Undecided → Medium
Brian Murray (brian-murray) wrote :

Steve Langasek believes that this is actually the BIOS displaying the blinking '_' and that there isn't anything we can do about this. Do you agree Colin?

Changed in grub2 (Ubuntu):
assignee: nobody → Colin Watson (cjwatson)
Colin Watson (cjwatson) wrote :

The BIOS does set the cursor at boot, and we can't do anything about that. It is possible that we may never be able to make it go away entirely. However, I think GRUB could perhaps turn it off a bit earlier; right now, it only turns it off when it's about to display the menu.

Changed in grub2 (Ubuntu Precise):
milestone: none → precise-alpha-2
Ivo Anjo (knuckles) wrote :

If I might add, I believe that at least in some cases this could be avoided.

I have grub2-efi on a macbook pro, and I still get the cursor (the machine is booting directly to grub, no other bootloader, bios, etc is loading).
If instead I use rEFIt as the first bootloader, I can see the rEFIt menu without any extra modesetting or flickering, which leads me to believe that it would be possible for grub to do the same.

Colin Watson (cjwatson) wrote :

Unless there's something weirder than usual going on in EFI, rEFIt appears to achieve this by turning off the cursor as one of its early initialisation steps; so it should be sufficient for GRUB to do the same.

I have a preliminary patch for this now which I'm testing. I'm afraid I got caught up in some build problems so it isn't quite going to make Alpha 2, but it should be no problem to land it just afterwards.

Changed in grub2 (Ubuntu Precise):
status: Triaged → In Progress
milestone: precise-alpha-2 → ubuntu-12.04-beta-1
Changed in ubuntu-flicker-free-boot:
status: New → In Progress
importance: Undecided → Medium
assignee: nobody → Colin Watson (cjwatson)
Martin Pitt (pitti) on 2012-03-02
Changed in grub2 (Ubuntu):
milestone: ubuntu-12.04-beta-1 → ubuntu-12.04-beta-2
Colin Watson (cjwatson) wrote :

I've added code to disable the cursor as early as sensibly possible in GRUB, and I still see a brief blinking cursor on my system. However, it's possible this will help on other systems, so I'll upload it anyway.

The remaining possibilities are:
 * the cursor is blinking while GRUB is uncompressing itself (it *might* be possible to add very early assembly code to disable the cursor, but to be honest I'm not sure I'm prepared to do this)
 * the cursor is blinking while the BIOS is loading GRUB, which we can do nothing about

Launchpad Janitor (janitor) wrote :
Download full text (4.0 KiB)

This bug was fixed in the package grub2 - 1.99-16ubuntu1

grub2 (1.99-16ubuntu1) precise; urgency=low

  * Resynchronise with Debian. Remaining changes:
    - Adjust for default Ubuntu boot options ("quiet splash").
    - Default to hiding the menu; holding down Shift at boot will show it.
    - Set a monochromatic theme and an appropriate background for Ubuntu.
    - Apply Ubuntu GRUB Legacy changes to legacy update-grub script.
    - Fix backslash-escaping in merge_debconf_into_conf.
    - Remove "GNU/Linux" from default distributor string.
    - Add crashkernel option.
    - Bypass menu unless other OSes are installed or Shift is pressed.
    - Allow Shift to interrupt 'sleep --interruptible'.
    - Reduce visual clutter in normal mode.
    - Remove verbose messages printed before reading configuration.
    - Suppress kernel/initrd progress messages, except in recovery mode.
    - Show the boot menu if the previous boot failed.
    - Don't generate device.map during grub-install or grub-mkconfig.
    - Adjust upgrade version checks for Ubuntu.
    - Suppress "GRUB loading" message unless Shift is held down.
    - Adjust versions of grub-doc and grub-legacy-doc conflicts.
    - Fix LVM/RAID probing in the absence of /boot/grub/device.map.
    - Look for .mo files in /usr/share/locale-langpack first.
    - Build-depend on qemu-kvm rather than qemu-system for grub-pc tests.
    - Check hardware support before using gfxpayload=keep.
    - Put second and subsequent Linux menu entries in a submenu.
    - Preferred resolution detection for VBE.
    - Set vt.handoff=7 for smooth handoff to kernel graphical mode.
    - Update default/grub.md5sum to include maverick's default md5sum.
    - In recovery mode, add nomodeset to the Linux kernel arguments, and
      remove the 'set gfxpayload=keep' command.
    - Skip Windows os-prober entries on Wubi systems, and suppress the menu
      by default if those are the only other-OS entries.
    - Handle probing striped DM-RAID devices.
    - Replace 'single' by 'recovery' when friendly-recovery is installed.
  * Use qemu -no-kvm in tests for now to work around LP #947597.
  * Disable cursor as early as possible in grub_main (LP: #861048).

grub2 (1.99-16) unstable; urgency=low

  * Backport from upstream:
    - Build with -fno-asynchronous-unwind-tables to save space (closes:

grub2 (1.99-15) unstable; urgency=low

  [ Adam Conrad ]
  * grub.cfg_400.patch: Redirect grep stdout to /dev/null since
    grub-mkconfig is "exec > grub.cfg.new", which causes grep's input
    and output to be the same FD (LP: #934269) (closes: #652972)
  * efi_disk_cache.patch: Bump the disk cache on EFI systems to
    dramatically reduce load times for vmlinux/initrd (LP: #944347)

  [ Colin Watson ]
  * no_libzfs.patch: Use xasprintf rather than asprintf.
  * Backport from upstream:
    - Rewrite XFS btree parsing; fixes invalid BMAP (closes: #657776).
    - Handle newer autotools, and add some missing quotes in the process.
      (Note that this moves grub-mkconfig_lib and update-grub_lib to
      /usr/share/grub; I added links in /usr/lib/grub for compatibility.)
    - Fix incorrect identifiers ...


Changed in grub2 (Ubuntu Precise):
status: In Progress → Fix Released
Colin Watson (cjwatson) on 2014-12-18
Changed in ubuntu-flicker-free-boot:
assignee: Colin Watson (cjwatson) → nobody
status: In Progress → Triaged
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