can't get keyboard input to work when using both serial and gfxterm GRUB terminal

[Brian Reichert]

I'm trying to configure GRUB2 to present on both gfxterm and a
serial console.

My grub config seems to allow for the presentation if the GRUB2
menu in both places, but the serial console does not seem to accept
keyboard events.

When the host is fully booted, and a login prompt is presented, I
am able to log in on the serial console, and interact with the
system.

If I set the GRUB_TERMINAL to just 'serial', I can indeed interact
with the GRUB2 menu.

Is this working for anyone else?

My specific environment is SLES 12 SP5 under Azure.

Misc packages:

  grub2-2.02-12.39.1.x86_64
  kernel-default-4.12.14-122.41.1.x86_64

Some of my directives in /etc/default/grub:

  GRUB_TIMEOUT=8
  GRUB_CMDLINE_LINUX_DEFAULT="splash=silent showopts resume=/dev/sda3 
crashkernel=100M,high crashkernel=72M,low console=tty1 console=ttyS0,115200n8 
earlyprintk=ttyS0,rootdelay=300 transparent_hugepage=never"
  GRUB_TERMINAL="gfxterm serial"
  #GRUB_TERMINAL="serial"
  GRUB_SERIAL_COMMAND="serial --unit=0 --speed=9600 --parity=no"

I'm happy to provide more particulars.

-- 
Brian Reichert                          <reichert@numachi.com>
BSD admin/developer at large