From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D52EC28EB3 for ; Thu, 6 Jun 2019 11:26:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 206322070B for ; Thu, 6 Jun 2019 11:26:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727063AbfFFL0p (ORCPT ); Thu, 6 Jun 2019 07:26:45 -0400 Received: from mga17.intel.com ([192.55.52.151]:12062 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726961AbfFFL0p (ORCPT ); Thu, 6 Jun 2019 07:26:45 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Jun 2019 04:26:44 -0700 X-ExtLoop1: 1 Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.157]) by fmsmga001.fm.intel.com with SMTP; 06 Jun 2019 04:26:41 -0700 Received: by lahna (sSMTP sendmail emulation); Thu, 06 Jun 2019 14:26:40 +0300 Date: Thu, 6 Jun 2019 14:26:40 +0300 From: Mika Westerberg To: "Rafael J. Wysocki" Cc: Bjorn Helgaas , "Rafael J. Wysocki" , Len Brown , Lukas Wunner , Keith Busch , Alex Williamson , Alexandru Gagniuc , ACPI Devel Maling List , Linux PCI Subject: Re: [PATCH 3/3] PCI / ACPI: Handle sibling devices sharing power resources Message-ID: <20190606112640.GA2781@lahna.fi.intel.com> References: <20190605145820.37169-1-mika.westerberg@linux.intel.com> <20190605145820.37169-4-mika.westerberg@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Thu, Jun 06, 2019 at 10:54:40AM +0200, Rafael J. Wysocki wrote: > On Wed, Jun 5, 2019 at 4:58 PM Mika Westerberg > wrote: > > > > Intel Ice Lake has an interated Thunderbolt controller which means that > > integrated Right :) > > the PCIe topology is extended directly from the two root ports (RP0 and > > RP1). Power management is handled by ACPI power resources that are > > shared between the root ports, Thunderbolt controller (NHI) and xHCI > > controller. > > > > The topology with the power resources (marked with []) looks like: > > > > Host bridge > > | > > +- RP0 ---\ > > +- RP1 ---|--+--> [TBT] > > +- NHI --/ | > > | | > > | v > > +- xHCI --> [D3C] > > > > Here TBT and D3C are the shared ACPI power resources. ACPI _PR3() method > > returns either TBT or D3C or both. > > > > Say we runtime suspend first the root ports RP0 and RP1, then NHI. Now > > since the TBT power resource is still on when the root ports are runtime > > suspended their dev->current_state is set to D3hot. When NHI is runtime > > suspended TBT is finally turned off but state of the root ports remain > > to be D3hot. > > It looks like this problem will affect all ACPI devices using power > resources and _PR3 in general, so fixing it just for PCI is not > sufficient IMO. Fair enough. > An alternative approach may be to set the state of a device that > dropped its references to power resources listed in _PR3 to D3cold > even though those power resources may be physically "on" at that time. > Everything else (including this patch AFAICS) will be racy this way or > another. OK, thanks for the comment. I'll try to look into this approach then.