From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755383AbcAOHB5 (ORCPT ); Fri, 15 Jan 2016 02:01:57 -0500 Received: from mga09.intel.com ([134.134.136.24]:57118 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754889AbcAOHBy (ORCPT ); Fri, 15 Jan 2016 02:01:54 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,298,1449561600"; d="scan'208";a="633779520" Subject: Re: [PATCH] i2c/designware: enable i2c controller to suspend/resume asynchronously To: Andy Shevchenko , Jarkko Nikula , Mika Westerberg , Wolfram Sang References: <567C0192.2050601@linux.intel.com> <568B848F.1070801@linux.intel.com> <1451996056.30729.394.camel@linux.intel.com> Cc: linux-i2c@vger.kernel.org, "linux-kernel@vger.kernel.org" , srinivas.kowtal@intel.com From: "Fu, Zhonghui" Message-ID: <5698995C.3070002@linux.intel.com> Date: Fri, 15 Jan 2016 15:01:48 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 MIME-Version: 1.0 In-Reply-To: <1451996056.30729.394.camel@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/5/2016 8:14 PM, Andy Shevchenko wrote: > On Tue, 2016-01-05 at 10:53 +0200, Jarkko Nikula wrote: >> Hi >> >> On 12/24/2015 04:30 PM, Fu, Zhonghui wrote: >>> Now, PM core supports asynchronous suspend/resume mode for devices >>> during system suspend/resume, and the power state transition of one >>> device may be completed in separate kernel thread. PM core ensures >>> all power state transition dependency between devices. This patch >>> enables designware i2c controllers to suspend/resume >>> asynchronously. >>> This will take advantage of multicore and improve system >>> suspend/resume >>> speed. After enabling all i2c devices, i2c adapters and i2c >>> controllers >>> on ASUS T100TA tablet, the system suspend-to-idle time is reduced >>> to >>> about 510ms from 750ms, and the system resume time is reduced to >>> about >>> 790ms from 900ms. >>> >> Nice reduction :-) >> >>> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c >>> b/drivers/i2c/busses/i2c-designware-platdrv.c >>> index 6b00061..395130b 100644 >>> --- a/drivers/i2c/busses/i2c-designware-platdrv.c >>> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c >>> @@ -230,6 +230,7 @@ static int dw_i2c_plat_probe(struct >>> platform_device *pdev) >>> } >>> >>> adap = &dev->adapter; >>> + device_enable_async_suspend(&pdev->dev); >>> adap->owner = THIS_MODULE; >>> adap->class = I2C_CLASS_DEPRECATED; >>> ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev- >>>> dev)); >> Does device_enable_async_suspend() need to be called before enabling >> runtime PM? I suppose not since there appears to have also related >> sysfs >> node for toggling it runtime. >> >> I'm thinking if you could move the device_enable_async_suspend() call >> into drivers/i2c/busses/i2c-designware-core.c: i2c_dw_probe() and >> then >> also PCI enumerated adapter could take advantage of it. > I concern about Intel BayTrail-T / Braswell / CherryTrail cases, since > we have non-trivial PM for LPSS there. Zhonghui, have you a chance to > stress test this on platforms based on mentioned SoCs? Because of long leave, so sorry for late reply. I understand what you said, if enable all LPSS devices suspend/resume asynchronously, the system can't resume sometimes on ASUS T100TA(BayTrail-T SoC). But, I have verified that the system can resume normally every time if enable only i2c controller async mode and let other LPSS devices in sync mode on ASUS T100TA. I have no Braswell and cherryTrail platforms, so no verification test on them. I have submitted a new version of this patch to move the device_enable_async_suspend() call into i2c_dw_proble() function - "[PATCH v2] i2c/designware: enable i2c controller to suspend/resume asynchronously". Thanks, Zhonghui > >