framebuffer loads under Linux, but not Xen

[Mike]

I posted this to the xen-users list, but it seems more like a GRUB issue now.

I recently built a Debian "Wheezy" system, which booted via GRUB to a
non-framebuffer console, printing

    Console: colour VGA+ 80x25

during boot. To /etc/default/grub I added

    GRUB_GFXMODE=1920x1200
    GRUB_GFXPAYLOAD_LINUX=keep

giving me the boot messages:

    vesafb: mode is 1920x1200x16, ...
    fbcon: VESA VGA (fb0) is primary device
    Console: switching to colour frame buffer device 240x75
    fb0: VESA VGA frame buffer device

But when I installed and booted Xen, it reverted to the non-fb console.
/dev/fb0 isn't present under dom0.

How do I enable a framebuffer console in dom0?

I notice that the /etc/grub.d/20_linux_xen script that generates the
/boot/grub/grub.cfg entries for Xen isn't calling out to the load_video
function, though it looks to me like it'd be called anyway in the
"if loadfont ..." block.

Do I need to pass a parameter to vmlinuz? video=?


Package: grub-common
Version: 1.99-27+deb7u2

Mobo is SuperMicro A1SRi-2558F, with an Aspeed AST2400.

grub.cfg
Description: Text document