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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
        David Vrabel <dvrabel@cantab.net>,
        Shannon Zhao <shannon.zhao@linaro.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        xen-devel <xen-devel@lists.xenproject.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [Xen-devel] [GIT PULL] xen: features and fixes for 4.8-rc0
Date: Thu, 28 Jul 2016 01:46:43 +0200
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On Wednesday, July 27, 2016 04:18:32 PM Linus Torvalds wrote:
> On Wed, Jul 27, 2016 at 4:09 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> >
> > The STAO definition document:
> >
> > http://wiki.xenproject.org/mediawiki/images/0/02/Status-override-table.pdf
> >
> > requires as to "operate as if that device does not exist", quite literally.
> 
> Well, first off, documentation is one thing, actually changing
> behavior is something entirely different.
> 
> Theory and practice are *not* the same.

Well, the STAO thing is totally new, so we have the documentation only ATM.

> The other worry I have is that I'd be happier if it's still visible in
> /sys/bus/acpi/ etc. Again, it's one thing to not react to it
> programmatically, and another thing entirely to actually hide the
> information from the rest of the system.
> 
> If I read that patch right, it will be hidden from sysfs too. But
> Maybe I'm mistaken.

You're right.

Avoiding to enumerate it entirely is somewhat simpler, because it allows
us to avoid some special casing in a few places IIRC.

I guess we can ask the author of the commit in question to come up with a
patch to unhide that device and we'll see how that looks like.

Thanks,
Rafael