e5f047be05
A regression in GRUB 2.12 causes the GRUB screen to become cluttered with artifacts from the previous screen whether it's the UEFI post UI, UEFI shell or any graphical UI running before GRUB. This issue occurs in situations like booting GRUB from the UEFI shell and going straight to the rescue or command shell causing visual discomfort. The regression was introduced by commit 2d7c3abd8 (efi/console: Do not set text-mode until it is actually needed). To address the screen flickering issue this commit suppresses the text-mode setting until the first output is requested. Before text-mode is set any attempt to clear the screen has no effect. This inactive period renders the clear screen ineffective in early boot stages, potentially leaving leftover artifacts that will clutter the GRUB console display, as there is no guarantee there will always be a clear screen after the first output. The issue is fixed by ensuring grub_console_cls() to work through lazy mode-setting, while also avoiding screen clearing for the hidden menu which the flicker-free patch aims to improve. Fixes: 2d7c3abd8 (efi/console: Do not set text-mode until we actually need it) Signed-off-by: Michael Chang <mchang@suse.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This is GRUB 2, the second version of the GRand Unified Bootloader. GRUB 2 is rewritten from scratch to make GNU GRUB cleaner, safer, more robust, more powerful, and more portable. See the file NEWS for a description of recent changes to GRUB 2. See the file INSTALL for instructions on how to build and install the GRUB 2 data and program files. See the file MAINTAINERS for information about the GRUB maintainers, etc. If you found a security vulnerability in the GRUB please check the SECURITY file to get more information how to properly report this kind of bugs to the maintainers. Please visit the official web page of GRUB 2, for more information. The URL is <http://www.gnu.org/software/grub/grub.html>. More extensive documentation is available in the Info manual, accessible using 'info grub' after building and installing GRUB 2. There are a number of important user-visible differences from the first version of GRUB, now known as GRUB Legacy. For a summary, please see: info grub Introduction 'Changes from GRUB Legacy'