From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: Re: [PATCH 01/10] i2c: add suspended flag and accessors for i2c adapters Date: Fri, 21 Dec 2018 11:43:13 +0100 Message-ID: <6fb7d574-9648-2960-5724-8b02a3348012@redhat.com> References: <20181219164827.20985-1-wsa+renesas@sang-engineering.com> <20181219223341.GA998@kunai> <2368540.q2jLLRDsj0@aspire.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <2368540.q2jLLRDsj0@aspire.rjw.lan> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: "Rafael J. Wysocki" Cc: Wolfram Sang , Lukas Wunner , Wolfram Sang , linux-i2c@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: linux-pm@vger.kernel.org Hi, On 20-12-18 22:09, Rafael J. Wysocki wrote: > On Thursday, December 20, 2018 11:00:29 AM CET Hans de Goede wrote: >> Hi, >> >> On 19-12-18 23:33, Wolfram Sang wrote: >>> Hi Lukas, Hans, >>> >>> On Wed, Dec 19, 2018 at 07:36:54PM +0100, Hans de Goede wrote: >>>> Hi, >>>> >>>> On 19-12-18 18:22, Lukas Wunner wrote: >>>>> On Wed, Dec 19, 2018 at 05:48:17PM +0100, Wolfram Sang wrote: >>>>>> +static inline void i2c_mark_adapter_suspended(struct i2c_adapter *adap) >>>>>> +{ >>>>>> + i2c_lock_bus(adap, I2C_LOCK_ROOT_ADAPTER); >>>>>> + set_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags); >>>>>> + i2c_unlock_bus(adap, I2C_LOCK_ROOT_ADAPTER); >>>>>> +} >>>>> >>>>> This looks like a duplication of the is_suspended flag in struct dev_pm_info. >>>>> Any reason why you can't use that? If so, it would be good to document the >>>>> reason in the commit message. >>>> >>>> Oh, that is a very good point and that one only gets set on system suspend >>>> and not on resume suspend, working around the problems with the i2c-designware >>> >>> Just to make it clear: you mean runtime suspend, not resume suspend, or? >> >> Yes I mean runtime-suspend, sorry. > > The power.is_suspended flag is about system-wide suspend, however. Right, which is why it is good for us to use, when runtime-suspend the i2c-adapter drivers transfer function will do a runtime_pm_get and all is well, we want to check for someone trying to do i2c-transfers on the adapter while it is system-suspended, since then the runtime_pm_get is a no-op and things fail. So for this use case it is a good thing that power.is_suspended flag is about system-wide suspend (which is what I was trying to say in the first place). Regards, Hans