Subject: Re: port-i386/8505: Some cyrix CPUs can be locked solid from userland
To: None <wennmach@geo.Uni-Koeln.DE>
From: Dave Sainty <>
List: netbsd-bugs
Date: 09/29/1999 09:19:47
"Dr. Lex Wennmacher" writes:

> I just run the code in question on my
> NetBSD 1.4 (HAL) #2: Sat Jun  5 23:50:38 MEST 1999
>     wennmach@hal:/usr/src/sys/arch/i386/compile/HAL
> cpu0: Cyrix 6x86 (486-class)
> No lockup, the program can be interrupted with ^C.
> Btw. it seems to me that there's a slight confusion concerning Cyrix CPUs in
> the 1.4 kernel: My "Cyrix 5x86-100QP" (I just opened my notebook to check the
> exact imprint on the CPU) gets detected as "Cyrix 6x86 (486-class)". The
> 486-class is right, but the 6x86 seems wrong, should read 5x86 instead.

I believe the lockup is restricted to pentium class CPUs.  This is the
one that crashes:

NetBSD 1.4K (CHARTREUSE) #20: Sun Sep 26 03:19:33 NZST 1999
cpu0: family 6 model 0 step 0
cpu0: Cyrix 6x86MX (686-class)

This is the one that doesn't:

NetBSD 1.4K (TEQUILA) #7: Fri Sep 17 23:43:58 NZST 1999
cpu0: family 6 model 0 step 0
cpu0: Cyrix 6x86MX (686-class)

Look depressingly similar huh? :)

If nothing else it may be probeable by reproducing it at boot time in
some recoverable manner.  Apparently the chip keeps running, just not
servicing interrupts.  Or maybe the workaround is relatively
inexpensive.  Not sure...