Re: v4.10-rc4 to v4.10-rc5: battery regression on Nokia N900

From: Pavel Machek
Date: Fri Jan 27 2017 - 14:14:13 EST

On Fri 2017-01-27 09:20:39, Guenter Roeck wrote:
> On Fri, Jan 27, 2017 at 10:40:33PM +0800, Zhang Rui wrote:
> > > >
> > > > If thermal zone I/F is used, we can not change it's 'type' name to
> > > > be
> > > > compatible with new hwmon API.
> > > >
> > > You mean you can not fix the name to be compatible with libsensors.
> > >
> >
> > We can try to convert it to a libsensor-compatible string, either for
> > hwmon only, or for both thermal and hwmon. But this is an ABI change,
> > right?
> Let's go back to the basics.
> Fact is that the thermal subsystem registers hwmon devices with 'name'
> attributes which violate the documented hardware monitoring ABI.
> I think we can consider this undisputed.
> The rest is pretty much all opinion.
> Is a change in a driver to stop violating a documented ABI an ABI change
> or a bug fix ? In other words, does a driver violating a documented ABI
> make that ABI violation part of the ABI ?

It can be both. But "no regressions" takes precedence over

> Quite interesting questions. My take is that it is a bug fix, others
> apparently have the strong opinion that potential users of such an ABI
> violation have priority, and that a violation of a documented ABI _does_
> make this violation part of the ABI.

"Potential" users you can work around. "Real" users are problem.

And yes, I have strong opinion about release candidates. Outside that,
see my next mail.

(cesky, pictures)

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