Fixing OpenBSD console mode for a new HDMI monitor

andrewmemoryblog@gmail.com (Andrew's Memory Blog) — Fri, 04 Jul 2025 22:56:08 -0700

My old monitor recently lost the magic smoke. I think it’s probably repairable with a new capacitor or two, but I took the opportunity to upgrade to an Acer SA272UE QHD monitor instead. It’s been good with one minor nit: when I switch to my OpenBSD firewall, I don’t get video.

That’s not quite true: I get video when the device (a HUNSN Micro Firewall Appliance, Mini PC, VPN, Router PC, Intel N5105, HUNSN RJ03, AES-NI, 4 x Intel 2.5GbE I226-V LAN, Type-C, TF, M.2 WiFi 6 Slot, Barebone, NO RAM, NO Storage, NO System) starts up in VGA mode. But once OpenBSD switches over to the framebuffer console, the monitor goes black and tells me Cable Not Connected.

The OpenBSD FAQ was not much help — it still references the old 80x50 text mode console rather than a framebuffer console. The BSD site daemonforums.org, however, had a wealth of information.

$ dmesg | grep wsdisplay
wsdisplay0 at inteldrm0 mux 1: console (std, vt100 emulation), using wskbd0
wsdisplay0: screen 1-5 added (std, vt100 emulation)

The recommended action was to boot to UKC — the kernel configurator — and disable the Intel DRM driver. I tried that, but wasn’t able to use it because of a five-year-old problem with USB keyboards.

So… I created /etc/bsd.reconfig and added the line:

/etc/bsd.reconfig

disable inteldrm0

After reboot, I saw

$ dmesg | grep wsdisplay
wsdisplay0 at efifb0 mux 1: console (std, vt100 emulation)
wsdisplay0: screen 1-5 added (std, vt100 emulation)
$ stty size
160 45

I’m still using the framebuffer console, but now with the EFI driver instead of the Intel driver. That’s cool — I can still run X if I need to, and I still get a 160x45 console.

I did run into one problem after doing this, which I’m not sure is related or not. When I installed patch 77_008, I saw:

Relinking to create unique kernel... failed!
!!! "/usr/libexec/reorder_kernel" must be run manually to install the new kernel

I typed in the magic command — that appeared to fix it. If that doesn’t persist, I might need to regenerate /var/db/kernel.SHA256.

Hdmi on Andrew's Memory Blog

Fixing OpenBSD console mode for a new HDMI monitor