xfree86 failure: mga_hal missing

[<tallison@tacocat.net>]

I have a very annoying problem with my XFree86 set up today.
I'm trying to get an installation from -testing and selected the
x-window-server to bring everything in.

No errors during installation.

No errors when I log in as 'root'

However, when I log in as a non-root user, it fails and I'm back at
the xdm window.

XFree86.0.log shows:
 (II) LoadModule: "vgahw"
(II) Loading /usr/X11R6/lib/modules/libvgahw.a
(II) Module vgahw: vendor="The XFree86 Project"
        compiled for 4.2.1.1, module version = 0.1.0
        ABI class: XFree86 Video Driver, version 0.5
(**) MGA(0): Depth 24, (--) framebuffer bpp 32
(==) MGA(0): RGB weight 888
(II) Loading sub module "mga_hal"
(II) LoadModule: "mga_hal"
(WW) Warning, couldn't open module mga_hal
(II) UnloadModule: "mga_hal"
(EE) MGA: Failed to load module "mga_hal" (module does not exist, 0)
(II) MGA(0): Matrox HAL module not loaded - using builtin mode setup instead
(--) MGA(0): Chipset: "mgag400" (G400)
(==) MGA(0): Using AGP 1x mode
(--) MGA(0): Linear framebuffer at 0xDC000000
(--) MGA(0): MMIO registers at 0xEFAFC000
(--) MGA(0): Pseudo-DMA transfer window at 0xEF000000
(--) MGA(0): BIOS at 0xEFAE0000
(II) Truncating PCI BIOS Length to 32768
(--) MGA(0): Video BIOS info block at offset 0x07A80
(WW) MGA(0): Video BIOS info block not detected!
(II) MGA(0): MGABios.RamdacType = 0x0

and /var/log/syslog has:
Nov 18 18:55:33 debian kernel: [drm:drm_init] *ERROR* Cannot initialize
the agpg
art module.
Nov 18 18:55:39 debian modprobe: modprobe: Can't locate module char-major-226
Nov 18 18:55:40 debian modprobe: modprobe: Can't locate module char-major-226
Nov 18 18:55:40 debian kernel: [drm:drm_init] *ERROR* Cannot initialize
the agpg
art module.

and /etc/X11/XF86Config-4:
Section "Module"
        Load    "GLcore"
        Load    "bitmap"
        Load    "dbe"
        Load    "ddc"
#       Load    "dri"
        Load    "extmod"
        Load    "freetype"
        Load    "glx"
        Load    "int10"
        Load    "record"
        Load    "speedo"
        Load    "type1"
        Load    "vbe"
EndSection


This really is strange, because I used to have this particular machine
running
as one of the best Debian machines I have.
Recently it was running Suse, but we had some differences...

But this has me stymied.