[Bug 1826453] [NEW] Grub2 Booting in blind mode due to "invalid video mode specification `text'"

[Dexuan Cui]

Public bug reported:

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 this is the upstream bug link:
https://savannah.gnu.org/bugs/?56217 .

Here this launchpad bug is for Ubuntu 16.04 and 14.04.

** Affects: grub2 (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1826453

Title:
  Grub2 Booting in blind mode due to "invalid video mode specification
  `text'"

Status in grub2 package in Ubuntu:
  New

Bug description:
  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 this is the upstream bug link:
  https://savannah.gnu.org/bugs/?56217 .

  Here this launchpad bug is for Ubuntu 16.04 and 14.04.

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