From mboxrd@z Thu Jan 1 00:00:00 1970 From: Len Brown Subject: Re: acpi_idle: Very idle Core i7 machine never enters C3 Date: Tue, 25 May 2010 11:40:25 -0400 (EDT) Message-ID: References: <20100126084740.GA5265@jgarrett.org> <87y6jkee1b.fsf@basil.nowhere.org> <20100205160900.GA2736@jgarrett.org> <20100426194002.586fbaa5@fido5> <20100427124703.GA16706@jgarrett.org> <20100430174447.GA14889@srcf.ucam.org> <20100525123701.GA7876@srcf.ucam.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: Received: from vms173005pub.verizon.net ([206.46.173.5]:59799 "EHLO vms173005pub.verizon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753935Ab0EYPkf (ORCPT ); Tue, 25 May 2010 11:40:35 -0400 In-reply-to: <20100525123701.GA7876@srcf.ucam.org> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Matthew Garrett Cc: Philip Langdale , Jeff Garrett , Andi Kleen , Linux Kernel Mailing List , linux-acpi@vger.kernel.org, luming.yu@intel.com, venki@google.com > > I'm told by the hardware guys that BM_STS is _not_ always > > a NOP, and so we're not supposed to simply ignore it on C3 -- > > though it should be extremely rare that we see it set. > > If it is ever set, it should go on and off depending on > > activity on some latency sensitive device, like out on the LPC. > > It may be possible for the BIOS writer to configure the chipset > > so that BM_STS is enabled always, presumably to accomodate > > some latency sensitve device -- or maybe by mistake. > > On some hardware we've seen BM_STS be enabled approximately 50% of the > time without any obvious cause. Assuming it is modern hardware, please get the acpidump and lspci -vv output from that harware to this bug report: https://bugzilla.kernel.org/show_bug.cgi?id=15886 thanks, -Len Brown, Intel Open Source Technology Center