Lost HDMI output on Dell XPS M1330

Some time since 10.3, I am no longer able to select HDMI output using
xrandr, just VGA.

Hints on how to get it back?

Noise follows:

== 10.3 ==
# uname -ap
FreeBSD m1330 10.3-RELEASE-p18 FreeBSD 10.3-RELEASE-p18 #0: Tue Apr 11
10:31:00 UTC 2017
root_at_amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC amd64
amd64

# kenv smbios.system.product
XPS M1330

# xrandr
Screen 0: minimum 320 x 200, current 1280 x 800, maximum 8192 x 8192
LVDS1 connected 1280x800+0+0 (normal left inverted right x axis y axis)
290mm x 180mm
1280x800 60.04*+
1024x768 60.00
800x600 60.32 56.25
640x480 59.94
VGA1 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)

# dmesg -a | egrep -i 'vga|drm'
vgapci0: <VGA-compatible display> port 0xeff8-0xefff mem
0xf6e00000-0xf6efffff,0xe0000000-0xefffffff irq 16 at device 2.0 on pci0
agp0: <Intel GM965 SVGA controller> on vgapci0
vgapci0: Boot video device
vgapci1: <VGA-compatible display> mem 0xf6f00000-0xf6ffffff at device 2.1
on pci0
sc0: VGA <16 virtual consoles, flags=0x300>
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
info: [drm] Initialized drm 1.1.0 20060810
drmn0: <Intel i965GM> on vgapci0
info: [drm] MSI enabled 1 message(s)
info: [drm] Supports vblank timestamp caching Rev 1 (10.10.2010).
info: [drm] Driver supports precise vblank timestamp query.
drmn0: taking over the fictitious range 0xe0000000-0xf0000000
info: [drm] initialized overlay support
info: [drm] Connector LVDS-1: get mode from tunables:
info: [drm] - kern.vt.fb.modes.LVDS-1
info: [drm] - kern.vt.fb.default_mode
info: [drm] Connector VGA-1: get mode from tunables:
info: [drm] - kern.vt.fb.modes.VGA-1
info: [drm] - kern.vt.fb.default_mode
info: [drm] Connector HDMI-A-1: get mode from tunables:
info: [drm] - kern.vt.fb.modes.HDMI-A-1
info: [drm] - kern.vt.fb.default_mode
fbd0 on drmn0
info: [drm] Initialized i915 1.6.0 20080730 for drmn0 on minor 0

== "Current" ==
# uname -ap
FreeBSD lenovo 12.0-CURRENT FreeBSD 12.0-CURRENT #0 r319078M: Sun May 28
20:22:51 EDT 2017 root_at_lenovo:/usr/obj/usr/src/sys/GENERIC-NODEBUG amd64
amd64

# kenv smbios.system.product
XPS M1330

# xrandr
Screen 0: minimum 320 x 200, current 1280 x 800, maximum 8192 x 8192
LVDS1 connected 1280x800+0+0 (normal left inverted right x axis y axis)
290mm x 180mm
1280x800 60.04*+
1024x768 60.00
800x600 60.32 56.25
640x480 59.94
VGA1 disconnected (normal left inverted right x axis y axis)

# dmesg -a | egrep -i 'vga|drm'
VT(vga): resolution 640x480
info: [drm] Initialized drm 1.1.0 20060810
vtvga0: <VT VGA driver> on motherboard
vgapci0: <VGA-compatible display> port 0xeff8-0xefff mem
0xf6e00000-0xf6efffff,0xe0000000-0xefffffff irq 16 at device 2.0 on pci0
agp0: <Intel GM965 SVGA controller> on vgapci0
acpi_video0: <ACPI video extension> on vgapci0
drmn0: <Intel i965GM> on vgapci0
intel_iicbb0 on drmn0
intel_iicbb1 on drmn0
intel_iicbb2 on drmn0
intel_iicbb3 on drmn0
intel_iicbb4 on drmn0
intel_iicbb5 on drmn0
info: [drm] MSI enabled 1 message(s)
info: [drm] Supports vblank timestamp caching Rev 1 (10.10.2010).
info: [drm] Driver supports precise vblank timestamp query.
intel_sdvo_ddc_proxy397632 on drmn0
intel_sdvo_ddc_proxy397664 on drmn0
drmn0: taking over the fictitious range 0xe0000000-0xf0000000
info: [drm] initialized overlay support
info: [drm] Connector LVDS-1: get mode from tunables:
info: [drm] - kern.vt.fb.modes.LVDS-1
info: [drm] - kern.vt.fb.default_mode
info: [drm] Connector VGA-1: get mode from tunables:
info: [drm] - kern.vt.fb.modes.VGA-1
info: [drm] - kern.vt.fb.default_mode
fbd0 on drmn0
VT: Replacing driver "vga" with new "fb".
info: [drm] Initialized i915 1.6.0 20080730 for drmn0 on minor 0
vgapci0: Boot video device
vgapci1: <VGA-compatible display> mem 0xf6f00000-0xf6ffffff at device 2.1
on pci0
acpi_video1: <ACPI video extension> on vgapci1

...keith