Messages in this thread | | | Date | Sun, 10 Sep 2023 13:50:37 -0700 | From | Zev Weiss <> | Subject | Re: [PATCH 3/3] Documentation: ABI: sysfs-driver-regulator-output |
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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
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