MGA G200 Driver fatal error during GPU init

[Oliver Smith-Denny]

Hi Dave,

     On kernel versions 4.20 and greater, the MGA G200
driver has a fatal error during GPU init and the KVM console
I use hangs. I still can ssh into the machine, however. The
log and some basic info is below. This error is 100%
reproducible for me, on different machines. With kernel 4.19, I don't 
see any error and the KVM console works correctly. Please let me know
if you need any more information. (Also, I wasn't sure which
email to use, the DRM drivers maintainer email is the linux.ie
one and the mgag200 maintainer email is the redhat.com one, so I sent it 
to both).

Thanks,
Oliver

[    2.297347] pstore: Unknown compression: deflate
[    2.297362] fbcon: Taking over console
[    2.297465] Console: switching to colour frame buffer device 128x48
[snip]
[    3.053910] fb0: switching to mgag200drmfb from simple
[    3.053946] Console: switching to colour dummy device 80x25
[    3.054377] [drm:mgag200_driver_load [mgag200]] *ERROR* can't reserve 
VRAM
[    3.054383] mgag200 0000:03:00.0: Fatal error during GPU init: -6


# lspci | grep -i vga

03:00.0 VGA compatible controller: Matrox Electronics Systems Ltd. MGA 
G200e [Pilot] ServerEngines (SEP1) (rev 42)

# modinfo mgag200

filename: 
/lib/modules/5.0.0-rc7-next-20190220+/kernel/drivers/gpu/drm/mgag200/mgag200.ko
license:        GPL
description:    MGA G200 SE
author:         Matthew Garrett
srcversion:     B5EC0E424CE53736E84252D
alias:          pci:v0000102Bd00000538sv*sd*bc*sc*i*
alias:          pci:v0000102Bd00000536sv*sd*bc*sc*i*
alias:          pci:v0000102Bd00000534sv*sd*bc*sc*i*
alias:          pci:v0000102Bd00000533sv*sd*bc*sc*i*
alias:          pci:v0000102Bd00000532sv*sd*bc*sc*i*
alias:          pci:v0000102Bd00000530sv*sd*bc*sc*i*
alias:          pci:v0000102Bd00000524sv*sd*bc*sc*i*
alias:          pci:v0000102Bd00000522sv*sd*bc*sc*i*
depends:        drm,drm_kms_helper,ttm,i2c-algo-bit
retpoline:      Y
intree:         Y
name:           mgag200
vermagic:       5.0.0-rc7-next-20190220+ SMP mod_unload modversions
parm:           modeset:Disable/Enable modesetting (int)