Re: [PATCH] gpio / ACPI: Allow shared GPIO event to be read via operation region

["Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>]

On Friday, October 30, 2015 09:17:41 PM Linus Walleij wrote:
> On Fri, Oct 30, 2015 at 11:02 AM, Mika Westerberg
> <mika.westerberg@xxxxxxxxxxxxxxx> wrote:
> 
> > In Microsoft Surface3 the GPIO detecting lid state is shared between GPIO
> > event and operation region. Below is simplied version of the DSDT from
> > Surface3 including relevant parts:
> (...)
> > To be able to go through acpi_gpio->events list for operation region access
> > we need to make sure the list is properly initialized whenever GPIO chip is
> > registered.
> >
> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=106571
> > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> 
> I wonder what an operation region is, maybe it's something you can eat.

That's a way for AML to access things.

Basically, if it wants to access a resource, it has to declare "I will be using
X bytes at location Y in address space Z" and the OS is supposed to provide
a handler for that.

Thanks,
Rafael

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