From patchwork Sun Feb 3 06:23:22 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aaron Lu X-Patchwork-Id: 217730 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 5C6072C008E for ; Sun, 3 Feb 2013 17:22:58 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751418Ab3BCGW5 (ORCPT ); Sun, 3 Feb 2013 01:22:57 -0500 Received: from mga03.intel.com ([143.182.124.21]:19098 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751204Ab3BCGW4 (ORCPT ); Sun, 3 Feb 2013 01:22:56 -0500 Received: from azsmga002.ch.intel.com ([10.2.17.35]) by azsmga101.ch.intel.com with ESMTP; 02 Feb 2013 22:22:54 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,591,1355126400"; d="scan'208";a="198168323" Received: from aaronlu.sh.intel.com ([10.239.36.111]) by AZSMGA002.ch.intel.com with ESMTP; 02 Feb 2013 22:22:31 -0800 Message-ID: <510E025A.9000103@intel.com> Date: Sun, 03 Feb 2013 14:23:22 +0800 From: Aaron Lu User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Alan Stern CC: Derek Basehore , James Bottomley , Jeff Garzik , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, SCSI development list , Linux-pm mailing list Subject: Re: [PATCH 1/2] don't wait on disk to start on resume References: In-Reply-To: Sender: linux-ide-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ide@vger.kernel.org On 02/02/2013 11:09 PM, Alan Stern wrote: > On Sat, 2 Feb 2013, Aaron Lu wrote: > >>>> An alternative way of possibly solving this problem from PM's point of >>>> view might be: >>>> 1 Set both ata port and scsi device's runtime status to RPM_SUSPENDED >>>> in their system suspend callback; > > By the way, what reason is there for doing this to the ATA port? Does > the port take a long time to resume, in the same way that a disk can > take a few seconds to spin back up? For SATA controllers that is in AHCI programming interface, the hard drive will be spined up when the link is put to active state, so the most time consuming part is in ata, not in scsi, as the below data showed on my computer(hard disk is a HDD attached to a sata controller in AHCI mode): The ata port resume callback takes several seconds(2s-5s) to finish, while sd_resume takes only 17ms... I'm not sure about other programming interfaces. > >> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c >> index 497adea..38000fc 100644 >> --- a/drivers/ata/libata-core.c >> +++ b/drivers/ata/libata-core.c >> @@ -5355,10 +5355,19 @@ static int ata_port_suspend_common(struct device *dev, pm_message_t mesg) >> >> static int ata_port_suspend(struct device *dev) >> { >> + int ret; >> + >> if (pm_runtime_suspended(dev)) >> return 0; >> >> - return ata_port_suspend_common(dev, PMSG_SUSPEND); >> + ret = ata_port_suspend_common(dev, PMSG_SUSPEND); >> + if (!ret) { >> + __pm_runtime_disable(dev, false); > > Don't you mean pm_runtime_disable(dev)? I don't think it is necessary to check_resume here, no? > >> + pm_runtime_set_suspended(dev); >> + pm_runtime_enable(dev); >> + } >> + >> + return ret; >> } >> >> static int ata_port_do_freeze(struct device *dev) >> @@ -5393,16 +5402,7 @@ static int ata_port_resume_common(struct device *dev, pm_message_t mesg) >> >> static int ata_port_resume(struct device *dev) >> { >> - int rc; >> - >> - rc = ata_port_resume_common(dev, PMSG_RESUME); >> - if (!rc) { >> - pm_runtime_disable(dev); >> - pm_runtime_set_active(dev); >> - pm_runtime_enable(dev); >> - } >> - >> - return rc; >> + return 0; >> } >> >> /* >> diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c >> index d9956b6..d0b6997 100644 >> --- a/drivers/scsi/scsi_pm.c >> +++ b/drivers/scsi/scsi_pm.c >> @@ -127,13 +127,21 @@ static int scsi_bus_prepare(struct device *dev) >> static int scsi_bus_suspend(struct device *dev) >> { >> const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; >> - return scsi_bus_suspend_common(dev, pm ? pm->suspend : NULL); >> + int ret; >> + >> + ret = scsi_bus_suspend_common(dev, pm ? pm->suspend : NULL); >> + if (!ret) { >> + __pm_runtime_disable(dev, false); >> + pm_runtime_set_suspended(dev); >> + pm_runtime_enable(dev); >> + } >> + >> + return ret; >> } >> >> static int scsi_bus_resume(struct device *dev) >> { >> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; >> - return scsi_bus_resume_common(dev, pm ? pm->resume : NULL); >> + return 0; >> } > > This doesn't look like it would work very well with something like a CD > drive, which doesn't use block-layer runtime PM. No problem, we have the in-kernel-event-poll to resume the CD. And actually, during resume, some udisk program will also open the block device to find something out, which will also resume the CD. > Is that what you meant when you talked about modifying the SCSI PM > callbacks? No, the modification is actually for disk. With v8 of block layer runtime PM, it is no longer the case runtime suspend is the same as system suspend for hard disk that utilize block layer runtime PM: we quiesce the device and run its suspend callback for the device during system suspend but we didn't touch the queue's rpm_status as we do in runtime_suspend callback. So I did some modifications to scsi_pm.c to make runtime suspend and system suspend do exactly the same thing for disk type scsi device, no matter if they are using block layer runtime PM or not. Probably I had better post code here, this is a replacement for the patch 4 of v8 block layer runtime PM patchset(I omit the sd part, since it is irrevelant), please kindly review, see if you like it :-) diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c index 8f6b12c..d9956b6 100644 --- a/drivers/scsi/scsi_pm.c +++ b/drivers/scsi/scsi_pm.c @@ -16,17 +16,44 @@ #include "scsi_priv.h" +static int sdev_blk_suspend(struct scsi_device *sdev) +{ + int err; + + err = blk_pre_runtime_suspend(sdev->request_queue); + if (err) + return err; + err = pm_generic_runtime_suspend(&sdev->sdev_gendev); + blk_post_runtime_suspend(sdev->request_queue, err); + + return err; +} + +static int sdev_blk_resume(struct scsi_device *sdev) +{ + int err; + + blk_pre_runtime_resume(sdev->request_queue); + err = pm_generic_runtime_resume(&sdev->sdev_gendev); + blk_post_runtime_resume(sdev->request_queue, err); + + return err; +} + static int scsi_dev_type_suspend(struct device *dev, int (*cb)(struct device *)) { + struct scsi_device *sdev = to_scsi_device(dev); int err; - err = scsi_device_quiesce(to_scsi_device(dev)); + err = scsi_device_quiesce(sdev); if (err == 0) { - if (cb) { + if (sdev->request_queue->dev) + err = sdev_blk_suspend(sdev); + else if (cb) err = cb(dev); - if (err) - scsi_device_resume(to_scsi_device(dev)); - } + + if (err) + scsi_device_resume(sdev); } dev_dbg(dev, "scsi suspend: %d\n", err); return err; @@ -34,11 +61,14 @@ static int scsi_dev_type_suspend(struct device *dev, int (*cb)(struct device *)) static int scsi_dev_type_resume(struct device *dev, int (*cb)(struct device *)) { + struct scsi_device *sdev = to_scsi_device(dev); int err = 0; - if (cb) + if (sdev->request_queue->dev) + err = sdev_blk_resume(sdev); + else if (cb) err = cb(dev); - scsi_device_resume(to_scsi_device(dev)); + scsi_device_resume(sdev); dev_dbg(dev, "scsi resume: %d\n", err); return err; } @@ -185,10 +215,18 @@ static int scsi_runtime_idle(struct device *dev) /* Insert hooks here for targets, hosts, and transport classes */ - if (scsi_is_sdev_device(dev)) - err = pm_schedule_suspend(dev, 100); - else + if (scsi_is_sdev_device(dev)) { + struct scsi_device *sdev = to_scsi_device(dev); + + if (sdev->request_queue->dev) { + pm_runtime_mark_last_busy(dev); + err = pm_runtime_autosuspend(dev); + } else { + err = pm_schedule_suspend(dev, 100); + } + } else { err = pm_runtime_suspend(dev); + } return err; }