bugGNU GRUB - Bugs: bug #56217, Grub2 Booting in blind mode due to...


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bug #56217: Grub2 Booting in blind mode due to "invalid video mode specification `text'"

Submitted by:  Dexuan Cui <decui>
Submitted on:  Thu 25 Apr 2019 08:17:16 PM UTC  
Category:  Booting Severity:  Major
Priority:  5 - Normal Item Group:  Software Error
Status:  None Privacy:  Public
Assigned to:  None Originator Name: 
Open/Closed:  Open Release: 
Release:  Git master Reproducibility:  Every Time
Planned Release:  None

Fri 26 Apr 2019 06:30:31 PM UTC, comment #3: 

BTW, the bug only affects a UEFI platform.

In the case of legacy BIOS platform, grub is able to support text mode and we don't see the "error: invalid video mode specification `text'. Booting in blind mode" message, though in this case grub also passes a zero of "lfb_base" to Linux kernel.

Dexuan Cui <decui>
Thu 25 Apr 2019 09:16:34 PM UTC, comment #2: 

Attached the patch; thanks Dexuan for pointing out that I need to do a better job upstreaming them ;)

Mathieu Trudel <cyphermox>
Thu 25 Apr 2019 08:29:22 PM UTC, comment #1: 

FYI: this is the bug link for Ubuntu 16.04 and 14.04:

Dexuan Cui <decui>
Thu 25 Apr 2019 08:17:16 PM UTC, original submission:  

In a Ubuntu 16.04.6 VM, which runs as a Gen2 VM on Hyper-V, I add GRUB_GFXPAYLOAD_LINUX="text" into /etc/default/grub and run update-grub; next, grub2 prints the below error:

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

This means grub2 passes a zero value for the "lfb_base" to
Linux kernel, which then fails to reserve the framebuffer MMIO range in drivers/hv/vmbus_drv.c: vmbus_reserve_fb(); as a result, when we pass through a PCIe device to the VM, the PCIe device may get a PCI MMIO BAR in the FB MMIO range, causing a conflict, and the PCIe device can not work in the VM.

The issue can not reproduce with Ubuntu 18.04. It turns out the grub2 in Ubuntu 18.04 has the below fix:

video: skip 'text' gfxpayload if not supported, to fallback to default (https://git.launchpad.net/~ubuntu-core-dev/grub/+git/ubuntu/commit/?id=38d9e2f862a96a039ae8ca8b87b8615d154ceda4

I'm asking the patch author (Mathieu Trudel-Lapierre) to submit the patch to the upstream grub, and hence I'm reporting this bug to track the issue. :-)  Once the fix is in the upstream grub, it would easier to ask the other Linux distros, e.g. RHEL 7.6, to also integrate the fix.

Dexuan Cui <decui>


Attached Files
file #46830:  skip_text_gfxpayload_where_not_supported.patch added by cyphermox (1KiB - text/x-patch - Attaching the aforementioned patch.)


Depends on the following items: None found

Items that depend on this one: None found


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  • -email is unavailable- added by cyphermox (Updated the item)
  • -email is unavailable- added by decui (Submitted the item)

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    Follows 1 latest change.

    Date Changed by Updated Field Previous Value => Replaced by
    2019-04-25 cyphermox Attached File- => Added skip_text_gfxpayload_where_not_supported.patch, #46830

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