Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755455Ab2BUOHh (ORCPT ); Tue, 21 Feb 2012 09:07:37 -0500 Received: from mail-vw0-f46.google.com ([209.85.212.46]:42600 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753358Ab2BUOHg convert rfc822-to-8bit (ORCPT ); Tue, 21 Feb 2012 09:07:36 -0500 MIME-Version: 1.0 In-Reply-To: References: <744357E9AAD1214791ACBA4B0B90926305BFDC@SHSMSX101.ccr.corp.intel.com> Date: Tue, 21 Feb 2012 22:07:35 +0800 X-Google-Sender-Auth: _2gjYb6F5SJjx1o8RwXVj1-zBnU Message-ID: Subject: Re: [RFC PATCH 2/6] ACPI: Reference devices in ACPI Power Resource From: Lin Ming To: Alan Stern Cc: "Zhang, Rui" , "Rafael J. Wysocki" , Jeff Garzik , Tejun Heo , Len Brown , "linux-kernel@vger.kernel.org" , "linux-ide@vger.kernel.org" , "linux-scsi@vger.kernel.org" , "linux-pm@vger.kernel.org" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2286 Lines: 55 On Fri, Feb 17, 2012 at 11:07 PM, Alan Stern wrote: > On Fri, 17 Feb 2012, Zhang, Rui wrote: > >> > Do you basically want >> > the ZPODD always to be suspended and resumed along with the ATA port, >> >> No. ZPODD suspends itself, which put ZPODD to a SCSI low power state (NOT power off/D3_COLD). >> And then it is the "Runtime PM core" that suspends ATA port after ZPODD being suspended. >> And the .runtime_suspend callback for ATA port actually turns off the ZPODD power. >> >> During resume, ATA port is resumed first because of the ACPI wakeup event. >> But in fact, this wakeup event should be read as "ZPODD remote wakeup signal", thus runtime resume request is sent to ZPODD, done by Patch 3/6. >> >> > or should it be possible to suspend the ZPODD while the port remains >> > running? >> > >> Sure, but the power is still on at this time. > > Then maybe you can use pm_runtime_no_callbacks() for the ZPODD device. > It's explained in Documentation/power/runtime_pm.txt, and I use it for > USB interfaces. If pm_runtime_no_callbacks() is used, runtime PM sysfs attributes won't be created. Then how to disable ZPODD feature in userspace? Currently, I use "control" file of scsi device to enable/disable ZPODD, for example echo auto > /sys/devices/pci0000:00/0000:00:1f.2/ata0/host1/target1:0:0/1:0:0:0/power/control echo on > /sys/devices/pci0000:00/0000:00:1f.2/ata0/host1/target1:0:0/1:0:0:0/power/control > > The idea is that the ZPODD will never receive any runtime PM callbacks > from the PM core. ?Instead the ATA port callback routines will be > responsible for power management of the ZPODD device. Does the ATA port callback also responsible to resume its child? For example, /sys/devices/pci0000:00/0000:00:1f.2/ata0/host1/target1:0:0/1:0:0:0/ ata0 is resumed. Then who will be responsible to resume host1, target1:0:0 and 1:0:0:0? Or do you mean that we don't need to resume these devices at all? host1 and target1:0:0 are logical devices, but I think 1:0:0:0 is not. Thanks, Lin Ming -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/