From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753402AbbETMh6 (ORCPT ); Wed, 20 May 2015 08:37:58 -0400 Received: from mx0b-0016f401.pphosted.com ([67.231.156.173]:64058 "EHLO mx0b-0016f401.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751928AbbETMh5 (ORCPT ); Wed, 20 May 2015 08:37:57 -0400 Date: Wed, 20 May 2015 20:34:30 +0800 From: Jisheng Zhang To: Mika Westerberg , CC: , , Subject: Re: [PATCH] i2c: designware: separate ops for system_sleep_pm and runtime_pm Message-ID: <20150520203430.24edd2a8@xhacker> In-Reply-To: <20150520121506.GU1490@lahna.fi.intel.com> References: <1431693099-2292-1-git-send-email-jszhang@marvell.com> <20150518082823.GH1490@lahna.fi.intel.com> <20150519203242.74617ad6@xhacker> <20150519131516.GO1490@lahna.fi.intel.com> <20150520193422.73de7d90@xhacker> <20150520121506.GU1490@lahna.fi.intel.com> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.25; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.14.151,1.0.33,0.0.0000 definitions=2015-05-20_03:2015-05-19,2015-05-20,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1402240000 definitions=main-1505200166 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dear Mika, On Wed, 20 May 2015 15:15:06 +0300 Mika Westerberg wrote: > On Wed, May 20, 2015 at 07:34:22PM +0800, Jisheng Zhang wrote: > > Sorry for confusion. Considering one platform which doesn't support power off > > the i2c host but it can disable the host's clock. So in such platform, when > > the host is runtime suspended, its clock is disabled, then i2c_dw_disable() will > > hang when s2ram. > > Right. This happens also when the platform powers off the device. > > > Except using the runtime pm API to ensure the host is in > > a correct state, is there any other solution? AFAIK, 'dev->power.direct_complete' > > doesn't help such case. > > What I had in mind is something like below: > > static int i2c_dw_prepare(struct device *dev) > { > return pm_runtime_suspended(dev); > } > > static void i2c_dw_complete(struct device *dev) > { > if (dev->power.direct_complete) > pm_request_resume(dev); > } > > In other words it checks if the device is already runtime suspended and > prevents ->suspend() etc. from being called. What amazing! I wrote the same code as yours after sending out the last email. > > If that does not work (I didn't try as this problem does not exist on It works! How to submit the patch? Do you mind if I cook the patch and add you signed-off? Thanks a lot, Jisheng