Re: [PATCH v2 2/3] hwmon: (pmbus/core): Add regulator event support

[Matti Vaittinen]

On 4/11/23 15:07, Mark Brown wrote:
> On Mon, Apr 10, 2023 at 11:19:41AM +0300, Matti Vaittinen wrote:
> > to 6. huhtik. 2023 klo 16.43 Mark Brown (broonie@xxxxxxxxxx) kirjoitti:
>
> > > I'm not sure what you're expecting there?  A device working with itself
> > > shouldn't disrupt any other users.
>
> > I have no concrete idea, just a vague uneasy feeling knowing that
> > devices tend to interact with each other. I guess it is more about the
> > amount of uncertainty caused by my lack of knowledge regarding what
> > could be done by these handlers. So, as I already said - if no one
> > else is bothered by this then I definitely don't want to block the
> > series. Still, if the error handling should be kept internal to PMBus
> > - then we should probably either say that consumer drivers must not
> > (forcibly) turn off the supply when receiving these notifications - or
> > not send these notifications from PMBus and allow PMBus to decide
> > error handling internally. (Again, I don't know if any in-tree
> > consumer drivers do turn off the supply regulator in error handlers -
> > but I don't think it is actually forbidden). Or am I just making  a
> > problem that does not exist?
>
> I think you are making a problem that doesn't exist.

In this case, sorry folks. I thought consumers could be more 'intrusive' 
with the handling of these notifications - which apparently is not true 
then. Guenter, I hope the statement from Mark cleared confusion I 
caused. I have no further questions about this series.

> > > Like I say I'm not sure how much practical difference it makes to think
> > > too hard about differentiating the errors.
>
> > I would do at least two classes.
>
> > 1) critical class - it is Ok for the consumer to forcibly shut down
> > the regulator, or maybe the whole system.
> > 2) warning class - it is not Ok to forcibly shut down the regulator.
>
> How severe an issue bad power is will be partly determined by what the
> consumer is doing with the power, it's going to be in a fairly narrow
> range but there is a range.

No longer related to this patch series - I am still trying to gather 
information where the "detection" level PMIC warning IRQs are used in 
real-world systems. This might give me some insight how these 
notifications are (or could be) used.

Yours,
	-- Matti

--
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

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