From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH] ACPI / platform / LPSS: disable async suspend/resume of LPSS devices Date: Tue, 23 Sep 2014 01:17:08 +0200 Message-ID: <2190534.fECTUJ0MGh@vostro.rjw.lan> References: <540E91F0.2060306@linux.intel.com> <54184C92.7060209@linux.intel.com> <54203616.2040803@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Return-path: Received: from v094114.home.net.pl ([79.96.170.134]:59216 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754119AbaIVW5W (ORCPT ); Mon, 22 Sep 2014 18:57:22 -0400 In-Reply-To: <54203616.2040803@linux.intel.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Fu, Zhonghui" Cc: Mika Westerberg , lenb@kernel.org, linux-acpi@vger.kernel.org, "linux-kernel@vger.kernel.org" On Monday, September 22, 2014 10:45:42 PM Fu, Zhonghui wrote: > [cut] > >>> > >>> This operation is reading data from Operation Region of one operand object in name space. I don't know the reason of hang at this point. Could you please give out some explanation about this? > >> I don't know the exact reason why this particular read hangs, but this means > >> that, perhaps, instead of disabling async suspend/resume for all LPSS devices > >> altogether, perhaps we can serialize their acpi_dev_resume_early()? > >> > >> Rafael > > Do you mean keeping other phases(prepare, suspend, suspend_late, suspend_noirq, resume_noirq, resume, complete) of suspend/resume asynchronous, and only serializing "resume_early" phase for all LPSS devices? > > > > Thanks, > > Zhonghui > Hi, Rafael > > Could you please confirm my understanding? This is not what I meant. Since we have a PM domain for the LPSS devices already, why don't we add an internal lock to that PM domain and acquire it over executing either acpi_dev_suspend_late() (during suspend) or acpi_dev_resume_early() (during resume) for all of them? -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.