Messages in this thread | | | Subject | Re: [PATCH 01/10] i2c: add suspended flag and accessors for i2c adapters | From | Hans de Goede <> | Date | Fri, 21 Dec 2018 11:43:13 +0100 |
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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
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