From owner-freebsd-acpi@FreeBSD.ORG Thu Feb 19 11:10:41 2009 Return-Path: Delivered-To: freebsd-acpi@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id EABF01065673; Thu, 19 Feb 2009 11:10:41 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140]) by mx1.freebsd.org (Postfix) with ESMTP id 005A38FC19; Thu, 19 Feb 2009 11:10:40 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from odyssey.starpoint.kiev.ua (beta-e.starpoint.kiev.ua [212.40.38.102]) by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id NAA10459; Thu, 19 Feb 2009 13:10:39 +0200 (EET) (envelope-from avg@icyb.net.ua) Message-ID: <499D3E2E.7090500@icyb.net.ua> Date: Thu, 19 Feb 2009 13:10:38 +0200 From: Andriy Gapon User-Agent: Thunderbird 2.0.0.19 (X11/20090110) MIME-Version: 1.0 To: Rui Paulo References: <498708FD.9030404@icyb.net.ua> <66885316-6F5B-4C56-BFE0-DBB86E050C99@freebsd.org> In-Reply-To: <66885316-6F5B-4C56-BFE0-DBB86E050C99@freebsd.org> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: freebsd-acpi@FreeBSD.org Subject: Re: piix4 and C2: patch for BRLD_EN_BM/ACPI_BITREG_BUS_MASTER_RLD X-BeenThere: freebsd-acpi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ACPI and power management development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 19 Feb 2009 11:10:42 -0000 on 02/02/2009 17:50 Rui Paulo said the following: > > On 2 Feb 2009, at 14:53, Andriy Gapon wrote: > >> >> Another patch for acpi_cpu code related to PIIX4 chipset. >> >> We do not support C3 with this chipset and as such we never touch >> ACPI_BITREG_BUS_MASTER_RLD when running on it. It's also possible >> (probable) that we never reset ACPI_BITREG_BUS_MASTER_STATUS (because of >> CPU_QUIRK_NO_BM_CTRL). >> So, if BIOS configures ACPI_BITREG_BUS_MASTER_RLD to 1 and >> ACPI_BITREG_BUS_MASTER_STATUS gets set to 1, we would get a situation >> where the system would always immediately break out of C2 state should >> we ever attempt to enter it. >> >> Actually, ACPI spec says that bus master activity need not break out of >> C2 state (only interrupts must do that). >> >> Given all of the above, it seems to be safe and desired to reset >> ACPI_BITREG_BUS_MASTER_RLD to zero with this chipset. >> >> The patch is successfully tested on a real system that exhibited the >> above behavior (immediate backout from cx_lowest of C2 to C1). > > > > Looks ok to me. I no longer have a PIIX4 system to test it, though. So, > if no one raises any objection, I'll commit it to HEAD in a few days. > > Andriy, if I forget, please ping me :-) Rui, may I commit this one now? :) -- Andriy Gapon