i386/104678: SMP not working on Turion XP Laptop

[Ariff Abdullah]

The following reply was made to PR i386/104678; it has been noted by GNATS.

From: Ariff Abdullah <ariff at FreeBSD.org>
To: bug-followup at FreeBSD.org, danolson at visi.com, rainer.alves at gmail.com,
        infofarmer at FreeBSD.org, bde at zeta.org.au
Cc: jhb at FreeBSD.org
Subject: Re: i386/104678: SMP not working on Turion XP Laptop
Date: Fri, 17 Nov 2006 17:15:01 +0800

 It seems the workaround is rather simple:
 
 machdep.cpu_idle_hlt=0
 
 Unfortunately, the only place where you can set that is after the
 system comes alive. This patch deals with that so that you can set it
 as early as possible during boot procedure through loader.conf.
 
 http://people.freebsd.org/~ariff/misc/turionX2.diff
 
 
 
 Summary:
 Basically the cpu enter deep sleep mode whenever it receives HLT
 call within idle loop, and that only if APIC + Local APIC timer is
 enabled. I can't tell whether it is because of APIC misseting, CPU bug
 or else, but one thing for sure, FreeBSD 5.x/SMP boots happily on this
 (well, that's because it doesn't use local APIC timer). With idle HLT
 disabled, there will be a slight power savings penalty especially if
 the cpu just sit idle doing nothing else.
 
 CPU Errata:
 http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/33610.pdf
 
 
 Perhaps jhb@ might have an interest in this issue.
 
 
 --
 Ariff Abdullah
 FreeBSD
 
 ... Recording in stereo is obviously too advanced
     and confusing for us idiot ***** users :P ........