From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bjorn Andersson Subject: Re: [PATCH] i2c: qup: Fix order of runtime pm initialization Date: Tue, 30 Sep 2014 13:03:30 -0700 Message-ID: <20140930200329.GV28481@sonymobile.com> References: <1412028051-21774-1-git-send-email-agross@codeaurora.org> <20140930015323.GE28481@sonymobile.com> <20140930195923.GB26928@qualcomm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Content-Disposition: inline In-Reply-To: <20140930195923.GB26928@qualcomm.com> Sender: linux-arm-msm-owner@vger.kernel.org To: Andy Gross Cc: Wolfram Sang , "linux-kernel@vger.kernel.org" , "linux-i2c@vger.kernel.org" , "Ivan T. Ivanov" , "linux-arm-msm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" List-Id: linux-i2c@vger.kernel.org On Tue 30 Sep 12:59 PDT 2014, Andy Gross wrote: > On Mon, Sep 29, 2014 at 06:53:24PM -0700, Bjorn Andersson wrote: > > On Mon 29 Sep 15:00 PDT 2014, Andy Gross wrote: > > > > > The runtime pm calls need to be done before populating the children via the > > > i2c_add_adapter call. If this is not done, a child can run into issues trying > > > to do i2c read/writes due to the pm_runtime_sync failing. > > > > > > > May I ask in what case this would fail? I thought we tested this as we found > > the faulty error check after calling pm_runtime_get_sync(). > > This is a different kind of failure. If during probe, the children do some I2C > activity, they will encounter issues with the runtime_sync due to the pm_runtime > not being initialized. However, once the qup probe completes, everything works > fine. > > The original runtime_sync issue revolved around the runtime_sync return value > being misinterpreted due to the incorrect check. > Yeah, I just wondered why my testing didn't trigger this. But I suspect that the answer is simply that the client I ran with did not do i2c accesses from probe. Regards, Bjorn