kernel goes dark on boot

[Emmanuel Dreyfus <manu%netbsd.org@localhost>]

Hello

An interesting problem on an all-in-one HP PC. Booting
NetBSD-10.0_BETA/amd64 (or prior versions) works fine until the
kernel starts displaying its messages. At that point the screen
turns dark.

I suspect a mode problem. In the boot prompt, gop displays:
*0: 1920x1080 BGRR pitch 1920 bpp 32
 1: 640x480 BGRR pitch 640 bpp 32
 2: 800x600 BGRR pitch 800 bpp 32
 3: 1024x768 BGRR pitch 1024 bpp 32
 4: 1280x1024 BGRR pitch 1280 bpp 32

Trying gop [1-3] causes the screen to go dark. But the machine is not
crashed, I can still type blindly gop 0 and get the display back.

If the kernel tries to select mode 1-3, that would explain the dark
screen. Is it a possible behavior? How can I change it?

-- 
Emmanuel Dreyfus
manu%netbsd.org@localhost