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

[Zev Weiss]

On Mon, Sep 04, 2023 at 05:24:31AM PDT, Mark Brown wrote:
> On Sun, Sep 03, 2023 at 05:48:14PM -0700, Zev Weiss wrote:
> > On Sun, Sep 03, 2023 at 06:04:23AM PDT, Greg Kroah-Hartman wrote:
>
> > > But yes, reading a sysfs should almost never cause a side affect at all.
>
> > > But what do you mean by "clear events?"
>
> > I mean that when the sysfs file is read, the state variable whose value it
> > exposes is also cleared as a side-effect (so the read operation "consumes"
> > the value it returns) -- see the implementation in patch 2 of this series
> > (specifically the 'data->events = 0' assignment in events_show()):
>
> It's a clear on read interrupt.

Sure, analogous behavior in hardware is reasonably common, but that 
doesn't strike me as a very compelling reason to design the 
kernel<->userspace interface to mimic it -- providing nicer interfaces 
than the raw hardware is one of the main reasons for having an OS in the 
first place, after all.


Zev