From owner-freebsd-current@FreeBSD.ORG Thu Jun 17 19:39:25 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CE95B16A4CE for ; Thu, 17 Jun 2004 19:39:25 +0000 (GMT) Received: from sccrmhc12.comcast.net (sccrmhc12.comcast.net [204.127.202.56]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2D9EE43D41 for ; Thu, 17 Jun 2004 19:39:24 +0000 (GMT) (envelope-from julian@elischer.org) Received: from interjet.elischer.org ([24.7.73.28]) by comcast.net (sccrmhc12) with ESMTP id <2004061719390801200hnsese>; Thu, 17 Jun 2004 19:39:09 +0000 Received: from localhost (localhost.elischer.org [127.0.0.1]) by InterJet.elischer.org (8.9.1a/8.9.1) with ESMTP id MAA79187; Thu, 17 Jun 2004 12:39:06 -0700 (PDT) Date: Thu, 17 Jun 2004 12:39:05 -0700 (PDT) From: Julian Elischer To: Don Bowman In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII cc: "'current@freebsd.org'" Subject: Re: STI, HLT in acpi_cpu_idle_c1 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 17 Jun 2004 19:39:26 -0000 On Thu, 17 Jun 2004, Don Bowman wrote: > > in the intel instruction manual, the effect > of STI is that interrupts are enabled > *after* the next instruction. > > ie: > > sti > ret > ... > > the return is still run with interrupts disabled > (if they were prior to the STI). > > In acpi_cpu_idle_c1, it does: > > sti > hlt > > shouldn't there be a NOP in there so that interrupts > are guaranteed on? I think your reading of it is right.. but I also think that if it was ALWAYS right we'd see processors go idle and never wake up again.... Since this doesn't seem to happen, maybe ther eis a bug in the emulator? We can always add a nop I guess and see what happens.. > > We have traced down a lockup of the system with > a TAP emulator, and found that three processors > are in acpi_cpu_idle with bit 9 of EFLAGS clear, > indicating interrupts are disabled. The fourth > processor is spinning with nothing to do (since > hardclock etc don't come to it). > > Suggestions? Am i off base on the sti/hlt? Is > there another problem that i might be running into? > > --don > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" >