bugGNU GRUB - Bugs: bug #59437, garbled GRUB screen on first boot


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bug #59437: garbled GRUB screen on first boot

Submitted by:  durdin
Submitted on:  Tue 10 Nov 2020 06:56:35 AM UTC  
Category:  Booting Severity:  Major
Priority:  5 - Normal Item Group:  Hardware-specific
Status:  None Privacy:  Public
Assigned to:  None Originator Name: 
Open/Closed:  Open Release: 
Release:  other Reproducibility:  Every Time
Planned Release:  None

Sat 14 Nov 2020 11:55:28 PM UTC, comment #2: 

As a followup I've verified that the same problems happen using grub 2.02 (the latest one thats distributed with centos 8).

David Lai <davidlai2020>
Sat 14 Nov 2020 06:53:19 PM UTC, comment #1: 

I am seeing a similar problem, It looks like grub doesnt "clear the screen" before outputting its countdown, etc...

I can hit "Esc" to stop the countdown, but the screen is garbled because grub is only painting the part of the screen it thinks is changed - leaving the other stuff thats already on the screen in its place.  scrolling around the screen using arrow keys does repaint some portions, but its still garbled.  hitting 'e' to edit the boot line DOES repaint the screen and it shows up nicely.

Interestingly enough I can get the screen to fully repaint the menu by using keys 'e' 'Escape' - which means: 1) goto edit mode 2) escape edit mode back to menu.  So this can be used as a (rather obfuscated) workaround.

I would vote for adding a 'control-L' key to grub to repaint the screen in interactive mode.  and/or adding an initial "clear screen" when grub first starts up.

I am enclosing screen shots to further illustrate the problem.  I am seeing this on Grub 0.97; not tested with grub2.

David Lai <davidlai2020>
Tue 10 Nov 2020 06:56:35 AM UTC, original submission:  

Affects: Grub version 2.04 (Debian)
Description: After Cold-Booting PC Bios/Uefi screen is displayed correctly, but when Grub2 is loaded and displays menu the entire screen become garbled and unreadable. This looks like as a cosmetic problem as in other aspects all works, you still could change boot parameters or change which entry to boot etc. Then immediately when Linux is booting (or windows) from this state the screen is again displaying correctly and text is readable. What is even more strange, after rebooting the grub is displayed correctly without any glitches.
Reproducibility: I've tested it on multiple main boards and combinations and looks like it only occurs when Dell-monitor is connected on my AMD graphics over DisplayPort cable. Unfortunately I do not have second monitor with DP or second cable to test if the problem is caused by cable itself, but GRUB is only one who causes screen to misbehave.
Grub settings are distribution-default, I haven't changed anything.



Attached Files
file #50304:  20201119_072527.jpg added by durdin (258KiB - image/jpeg - My original problem is bit different, as hitting esc has no difference. Only way to fix it is to power-cycle, which redraws screen correctly.)
file #50278:  grub01.png added by davidlai2020 (43KiB - image/png - screenshots to show garbled screen)
file #50279:  grub03.png added by davidlai2020 (27KiB - image/png - screenshots to show garbled screen)
file #50280:  grub02.png added by davidlai2020 (55KiB - image/png - screenshots to show garbled screen)
file #50281:  grub04.png added by davidlai2020 (30KiB - image/png - screenshots to show garbled screen)


Depends on the following items: None found

Items that depend on this one: None found


Carbon-Copy List
  • -email is unavailable- added by davidlai2020 (Updated the item)
  • -email is unavailable- added by durdin (Submitted the item)

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    Follow 5 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2020-11-19 durdin Attached File- => Added 20201119_072527.jpg, #50304
    2020-11-14 davidlai2020 Attached File- => Added grub01.png, #50278
        Attached File- => Added grub03.png, #50279
        Attached File- => Added grub02.png, #50280
        Attached File- => Added grub04.png, #50281

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