I'm trying to get console output on both the onboard iGPU (Intel i915, HDMI output) and the AST BMC (IPMI remote display) on my headless server setup.

Hardware and OS

• Motherboard: ASUS Pro WS W680-ACE IPMI
• CPU: Intel i9-14900
• OS: Ubuntu 24.04.2 LTS (Pro), kernel 6.8.0-60-generic, UEFI boot
• systemd is in use and default GRUB is installed

BIOS Settings

All relevant GPU-related options are enabled:

Primary Display       [CPU Graphics]
iGPU Multi-Monitor    [Enabled]
DVMT Pre-Allocated    [64M]
RC6 (Render Standby)  [Enabled]

When I boot into the BIOS firmware setup, both HDMI and IPMI outputs mirror the BIOS screen correctly, confirming that hardware-level multi-display support is working.

Framebuffer Devices

After booting Linux:

$ ls /dev/fb*
/dev/fb0  /dev/fb1

$ cat /sys/class/graphics/fb*/name
i915drmfb
astdrmfb

So:

• /dev/fb0 = Intel iGPU (HDMI)
• /dev/fb1 = AST BMC (IPMI)

What I’ve Tried

I’ve tried modifying /etc/default/grub with various combinations of fbcon=map: and console=ttyX:

1. GRUB_CMDLINE_LINUX_DEFAULT="fbcon=map:1,0 console=tty1 console=tty2" → Only IPMI (fb1) works, HDMI stays black.

2. GRUB_CMDLINE_LINUX_DEFAULT="fbcon=map:0,1 console=tty1 console=tty2" → Only HDMI (fb0) works, IPMI stays black.

3. GRUB_CMDLINE_LINUX_DEFAULT="fbcon=map:both console=tty1 console=tty2" → Nothing appears on either display.

(Yes, I realize fbcon=map:1,0 maps tty1 to fb1 and tty2 to fb0 — that behavior is expected.)

I also enabled [email protected] and confirmed it’s running.

What I Want

• Ideally: Same console output mirrored on both HDMI and IPMI
• Acceptable: Separate virtual terminals (e.g., tty1 on IPMI, tty2 on HDMI)

But so far I can only get one to work at a time, depending on how I order fbcon=map.

Any suggestions? Is this a limitation in fbcon, the kernel, or something I can work around with udev, early KMS, or a boot service?