From mboxrd@z Thu Jan  1 00:00:00 1970
From: Bill Davidsen <davidsen@tmr.com>
Subject: Re: [ACPI] Re: Linux 2.4.26-rc1 (cmpxchg vs 80386 build)
Date: Tue, 30 Mar 2004 15:08:50 -0500
Sender: linux-kernel-owner@vger.kernel.org
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To: Len Brown <len.brown@intel.com>
Cc: Chris Friesen <cfriesen@nortelnetworks.com>, Willy Tarreau <willy@w.ods.org>, "Richard B. Johnson" <root@chaos.analogic.com>, Alan Cox <alan@lxorguk.ukuu.org.uk>, Arkadiusz Miskiewicz <arekm@pld-linux.org>, Marcelo Tosatti <marcelo.tosatti@cyclades.com>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, ACPI Developers <acpi-devel@lists.sourceforge.net>
List-Id: linux-acpi@vger.kernel.org

Len Brown wrote:
> Sorry I didn't reply to this thread, after Alan wrote I figured
> the topic was closed;-)
> 
> Yes, per my initial message, gcc _will_ generate cmpxchg for the 80386
> build.  Indeed, it has been doing so for over a year with ACPI's
> previous private (and flawed) asm() invocation of cmpxchg.
> 
> Andi/Alan suggested we invoke cmpxchg always in ACPI,
> but disable ACPI at boot-time in the unlikely event we find
> ourselves running on a cpu without that instruction.

Is there no reasonable way to avoid using it in ACPI? It's not as if 
performance was critical there, or the code gets run often. Too bad it 
can't just be emulated like floating point, but I don't think it can on SMP.

I have to think Alan is right as usual.

-- 
    -bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
  last possible moment - but no longer"  -me