FreeBSD 14.3 - HDMI Hot-Plug only works on the first try.

claudiuschan · 2025-11-26T15:02:50+0000

Dear BSD friends,

I have X1-carbon Thinkpad that works properly and running FreeBSD 14.3. It's been really great running so far. I just have one particular issue on the HDMI hot-plug.

Issue Description
When I connect the laptop HDMI output to a 4K TV. It works for the first time when the laptop fresh from boot.

But when I unplug the HDMI cable and plug in the 2nd time, it doesn't detect the 4K TV anymore.

I tried the same procedures with Xorg (i3) & Wayland (Sway). Same results, which I suspect is due to the drm-kmod driver.

I tried both the drm-515-kmod & drm-61-kmod, both have the same results as well, only works on the first try.

I also capture the drm debug log from /var/log/messages, but not sure if it provides any help I attached here for reference.

Enable debug on drm via kernel knob:
sudo sysctl dev.drm.__drm_debug=-1

If anyone can provide any help or explanation would be great.

If not I will just stick to 2nd option. use USB-to-HDMI dongle, but It would be less ideal due to I cannot route audio to my TV using the dongle.

Hardware Information

Code:

Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz (2100.00-MHz K8-class CPU)

➜  ~ pciconf -lv|grep -B4 VGA
vgapci0@pci0:0:2:0:    class=0x030000 rev=0x07 hdr=0x00 vendor=0x8086 device=0x5917 subvendor=0x17aa subdevice=0x225c
    vendor     = 'Intel Corporation'
    device     = 'UHD Graphics 620'
    class      = display
    subclass   = VGA

Steps to reproduce
1. Boot the laptop from poweroff.
2. Enter Window Manager (i3/sway)
3. Plug in HDMI cable to laptop HDMI port.
4. 4K TV displays the workspace working
5. Unplug the HDMI cable.
6. Try 2nd time, it is not working.

FreeBSD 14.3 - HDMI Hot-Plug only works on the first try.

claudiuschan

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