kern/56853: re-instate vga* support for XEN3_DOM0

[kardel%netbsd.org@localhost]

>Number:         56853
>Category:       kern
>Synopsis:       re-instate vga* support for XEN3_DOM0
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon May 23 13:30:00 +0000 2022
>Originator:     kardel%netbsd.org@localhost
>Release:        NetBSD 9.99.96
>Organization:
	
>Environment:
	
	
System: NetBSD toblerone.hw.abs.acrys.com 9.99.96 NetBSD 9.99.96 (XEN3_DOM0) #2: Thu May 19 20:42:31 CEST 2022  kardel@pip:/src/NetBSD/cur/src/obj.amd64/sys/arch/amd64/compile/XEN3_DOM0 amd64
Architecture: x86_64
Machine: amd64
>Description:
	Booting XEN3_DOM0 9.99.96 on a Supermicro ends up with a black screen after the Xen boot messages.
	Turns out the vga0 is not attached as it is not configured for XENPV - see XEN3_DOM0.
	#vga*           at pci? dev ? function ?# Needs acpi_md_vbios_reset
						# in acpi_wakeup.c (!xenpv)
	dmesg:
	ppb38 at pci41 dev 0 function 0: ASPEED Technology AST1150 PCIe-to-PCI bridge (rev. 0x04)
	ppb38: PCI Express capability version 2 <PCI-E to PCI/PCI-X Bridge>
	pci42 at ppb38 bus 200
	pci42: i/o space, memory space enabled
	ASPEED Technology ASPEED Graphics Family (VGA display, revision 0x41) at pci42 dev 0 function 0 not configured

	In 9.99.55 vga0 did attach.
	vga0 at pci42 dev 0 function 0: vendor 1a03 product 2000 (rev. 0x41)
	wsdisplay0 at vga0 kbdmux 1: console (80x25, vt100 emulation)

	As these ASPEED VGA/BMC/IPMI devices are in many of the larger servers dropping VGA device support is
	a serious regression.

	Originating PR kern/55667

>How-To-Repeat:
	Boot XEN3_DOM0 9.99.96 on a server with ASPEED VGA graphics. observe a black screen.
>Fix:
	revisit VGA support for XENPV

>Unformatted: