Problems with hyper-threading on Asus P4T533 / Linux 2.4.20

[Lars Magne Ingebrigtsen <larsi@gnus.org>]

We've just gotten an Asus P4T533-based machine with a 3.06GHz P4 CPU,
bios version 1005.  (P4T533 is i850e-based.)  The bios claims that the
P4 has hyper-threading, and as you can see from the cpuinfo output
below, "ht" is among the flags.  (And the manual says that P4T533 is
ht-enabled.)

I've tried booting with acpismp=force and without, and it doesn't
seem to make much difference: Linux still only sees a single CPU.
I've also tried 2.4.21-pre4 and -ac4, which doesn't seem to make any
difference, either.

Anybody got any ideas why I can't get this to work?

buto:~# uname -a
Linux buto 2.4.20 #3 SMP Wed Feb 12 14:28:49 CET 2003 i686 unknown
buto:~# cat /proc/cpuinfo 
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 2
model name      : Intel(R) Pentium(R) 4 CPU 3.06GHz
stepping        : 7
cpu MHz         : 3073.691
cache size      : 512 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm
bogomips        : 6134.16


-- 
(domestic pets only, the antidote for overdose, milk.)
   larsi@gnus.org * Lars Magne Ingebrigtsen