Invisible text with drm on radeon amd64

[David Brownlee <abs%absd.org@localhost>]

Running NetBSD 7.0_RC1 (GENERIC.201507162340Z) on an asus
motherboard.with built in 760G [Radeon 3000].

When drm is configured the text switches to black on the black
background (the cursor is still visible).

Relevant lines from dmesg below.

Has anyone else seen this?

As an aside - given we have boot -1 and boot -2 to disable ACPI and
SMP, would it make sense to add a boot -3 flag to be able to disable
drm?

radeon0 at pci1 dev 5 function 0: vendor 0x1002 product 0x9616 (rev. 0x00)
drm: initializing kernel modesetting (RS780 0x1002:0x9616 0x1043:0x8388).
drm: register mmio base: 0xfbef0000
drm: register mmio size: 65536
drm kern info: ATOM BIOS: B27722_RS780C
radeon0: info: VRAM: 32M 0x00000000C0000000 - 0x00000000C1FFFFFF (32M used)
radeon0: info: GTT: 512M 0x00000000A0000000 - 0x00000000BFFFFFFF
drm: Detected VRAM RAM=20M, BAR=32M
drm: RAM width 32bits DDR
drm: radeon: 32M of VRAM memory ready
drm: radeon: 512M of GTT memory ready.
drm: Loading RS780 Microcode
drm: GART: num cpu pages 131072, num gpu pages 131072
drm: PCIE GART of 512M enabled (table at 0x00000000C0040000).
radeon0: info: WB enabled
radeon0: info: fence driver on ring 0 use gpu addr 0x00000000a0000c00
and cpu addr 0x0xffff800048b96c00
drm: Supports vblank timestamp caching Rev 2 (21.10.2013).
drm: Driver supports precise vblank timestamp query.
radeon0: interrupting at ioapic0 pin 18 (radeon)
drm: radeon: irq initialized.
drm: ring test on 0 succeeded in 1 usecs
drm: ib test on ring 0 succeeded in 0 usecs
drm: Radeon Display Connectors
drm: Connector 0:
drm:   VGA-1
drm:   DDC: 0x7e40 0x7e40 0x7e44 0x7e44 0x7e48 0x7e48 0x7e4c 0x7e4c
drm:   Encoders:
drm:     CRT1: INTERNAL_KLDSCP_DAC1
drm: Connector 1:
drm:   DVI-D-1
drm:   HPD1
drm:   DDC: 0x7e50 0x7e50 0x7e54 0x7e54 0x7e58 0x7e58 0x7e5c 0x7e5c
drm:   Encoders:
drm:     DFP3: INTERNAL_KLDSCP_LVTMA
radeon0: info: No connectors reported connected with modes
drm: Cannot find any crtc or sizes - going 1024x768
radeondrmkmsfb0 at radeon0
radeon0: info: registered panic notifier
radeondrmkmsfb0: framebuffer at 0xffff800048da7000, size 1024x768,
depth 8, stride 1024
wsdisplay0 at radeondrmkmsfb0 kbdmux 1: console (default, vt100 emulation)