Bug 297231 - Do not halt the system when some firmware is missing
Summary: Do not halt the system when some firmware is missing
Status: Open
Alias: None
Product: Base System
Classification: Unclassified
Component: wireless (show other bugs)
Version: 16.0-CURRENT
Hardware: Any Any
: --- Affects Some People
Assignee: Bjoern A. Zeeb
URL:
Keywords:
Depends on:
Blocks: 273623
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Reported: 2026-08-02 07:33 UTC by Thierry Thomas
Modified: 2026-08-04 15:49 UTC (History)
1 user (show)

See Also:

Attachments
dmesg.today (72.97 KB, text/plain)
2026-08-02 07:33 UTC, Thierry Thomas 		no flags Details
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Description Thierry Thomas freebsd_committer freebsd_triage 2026-08-02 07:33:34 UTC 
Created attachment 273392 [details]
dmesg.today

1) Particular case - MediaTek mt7921
On a laptop running 16.0-CURRENT main-n287724-4bae864a6467 (July 28 2026), with the patches described at
https://lists.freebsd.org/archives/freebsd-wireless/2026-July/004372.html
the WiFi stuff has been loaded, but the Bluetooth part is missing, and the system  halts.
A screen capture is available at
https://thierry.lautre.net/FreeBSD/MissingFirmwareSystemHalted.jpg

To solve the problem, it is necessary to reboot in single user mode, and to add this line in /etc/rc.conf:
devmatch_blocklist="${devmatch_blacklist} if_mt7921"

2) General case
When some firmware file is missing, for any reason, do not halt the system, but just ignore the corresponding device.

dmesg attached
Comment 1 Thierry Thomas freebsd_committer freebsd_triage 2026-08-02 07:34:12 UTC 
Assign to bz, as seen by mail.
Comment 2 Bjoern A. Zeeb freebsd_committer freebsd_triage 2026-08-02 14:00:57 UTC 
Oh, it completely hangs and you have to power cycle by pressing the power button?
I somehow thought it panics.
I think I shouldn't read emails in the middle of the hot nights these days.
This may be mt76 specific after all then.

Is this a DEBUG kernel (WITNESS, INVARIANTS)?
Can you at that point still break to the debugger?
Comment 3 Thierry Thomas freebsd_committer freebsd_triage 2026-08-02 14:06:51 UTC 
(In reply to Bjoern A. Zeeb from comment #2)

Yes, I had to power cycle by pressing the power button.

ATM I'm working on some big ports, and I removed the DEBUG stuff.
I'll rebuild a new kernel with it when it will be finished.
Comment 4 Bjoern A. Zeeb freebsd_committer freebsd_triage 2026-08-04 15:49:37 UTC 
I believe this is an issue specific to mt76 so change Blocks despite my original thinking it may be generic.

Could likely also be related to
https://cgit.freebsd.org/src/commit/?id=baf8561bdc3f39c542a82cd1235fbf4bf97b4310