Re: [PATCH 3/3] Documentation: ABI: sysfs-driver-regulator-output

[Zev Weiss]

On Wed, Sep 20, 2023 at 03:48:00AM PDT, Greg Kroah-Hartman wrote:
> On Wed, Sep 20, 2023 at 03:44:29AM -0700, Zev Weiss wrote:
> > On Wed, Sep 20, 2023 at 02:29:15AM PDT, Greg Kroah-Hartman wrote:
> > > On Wed, Sep 20, 2023 at 02:02:49AM -0700, Zev Weiss wrote:
> > > >  static int regulator_userspace_notify(struct notifier_block *nb,
> > > >  				      unsigned long event,
> > > >  				      void *ignored)
> > > >  {
> > > >  	struct userspace_consumer_data *data =
> > > >  		container_of(nb, struct userspace_consumer_data, nb);
> > > > -	static const char * const *envp[] = { "NAME=events", NULL };
> > >
> > > You removed this user/kernel api value, what will break if you do that?
> > >
> >
> > Sorry, I don't follow -- what removal are you referring to?  The envp array
> > still has a NAME entry -- I changed its value from "events" to "event",
>
> Yes, that value.
>
> > but
> > I wrote that part before I realized that the 'event' parameter of the
> > function was actually a bitmask that might convey multiple events and just
> > forgot to change it back, so keeping it pluralized is probably more
> > appropriate.
> >
> > And FWIW, I didn't intend for the exact format of the EVENT parameter that I
> > sketched there to be something that had to be kept; given that there might
> > be multiple entries perhaps it'd be better to use separate parameters more
> > like NUMEVENTS, EVENT0, EVENT1, etc?  (Or omit NUMEVENTS and just let the
> > consumer count upward until it doesn't find a match.)
>
> I don't know, what does userspace do with this value today?  If you
> change it, what will break?

Unless there's something I'm not aware of, this is an entirely new 
interface being added, not a change to an existing one, so I don't think 
there's any existing userspace beyond draft/experimental code.  My patch 
was a relative one on top of Naresh's patch 2/3 in this series as a 
proposed amendment to it; the userspace-consumer driver as it presently 
exists in the mainline kernel doesn't have a uevent interface at all.


Zev