boot hang with certain Phenom II cpu models

Sascha Klauder sascha at
Thu Dec 13 11:15:41 UTC 2018

Hi all,

 I've recently upgraded my Athlon II based home box (happily
running FreeBSD for several years) to a Phenom II X4 960T CPU.
Now, kernel (11.2) hangs in early hardware initialization.

 Mainboard is a nForce 720 based Gigabyte GA-M720-US3 rev 1.0,
BIOS is latest and the CPU is on Gigabyte's CPU support list
for this board. 

 A parallel Windows 7 installation continues to work flawlessly
and the system is stable running prime95.  Memtest86 reports no
errors.  I've tried several other OS boot media (DragonFly 5.4,
OpenBSD 6.4, Linux 4.9) -- all boot fine with no problems (see
dmesg output linked below).

 I've found two very similiar problem reports on the FreeBSD
forums.  Both involve Phenom II cpu's and nForce-based mainboards,
so I think we're missing some BIOS/ACPI quirk here.

 So far, I tried (unsuccessfully) to disable obvious ACPI sub-
systems (cpu, mwait, quirks) and debug settings (acpi.cpu_unordered,
acpi.max_threads).  Anyone got a hint where to look or debug this

kernel boot messages (obtained from 10.4 amd64):

boot messages with the previous Athlon II cpu in this system:

boot messages from DFly, OpenBSD and Linux:


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