From mboxrd@z Thu Jan  1 00:00:00 1970
From: catalin.marinas@arm.com (Catalin Marinas)
Date: Tue, 6 Jan 2015 14:16:30 +0000
Subject: [PATCH v5 18/18] Documentation: ACPI for ARM64
In-Reply-To: <2647669.mQf6pODdjV@wuerfel>
References: <1413553034-20956-1-git-send-email-hanjun.guo@linaro.org>
 <54ABC2CB.6@linaro.org>
 <20150106112929.GB8829@e104818-lin.cambridge.arm.com>
 <2647669.mQf6pODdjV@wuerfel>
Message-ID: <20150106141630.GG8829@e104818-lin.cambridge.arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, Jan 06, 2015 at 02:05:12PM +0000, Arnd Bergmann wrote:
> On Tuesday 06 January 2015 11:29:29 Catalin Marinas wrote:
> > > >> We will work on this both on ASWG and linux ACPI driver side, as Dong
> > > >> and Charles pointed out, _OSI things can be solved in ACPI spec, when
> > > >> that is done, we can modify the kernel driver to fix the problems above.
> > > >
> > > > Which driver?
> > > 
> > > the ACPICA core driver as you suggested, sorry for the confusion.
> > > 
> > > > What about ACPI_OS_NAME? Would you suggest it is fine to report
> > > > "Microsoft Windows NT" on an ARM system? That _OS_ not _OSI.
> > > 
> > > No, not at all. I prefer "Linux"
> > > In include/acpi/acconfig.h, when ACPI_OS_NAME defined, it says:
> > > "OS name, used for the _OS object.  The _OS object is essentially
> > > obsolete,..."
> > > for some legacy reasons, we needed  "Microsoft Windows NT", but ACPI
> > > for ARM64 on linux is totally new, I think we can change it to
> > > "Linux" when CONFIG_ARM64 as you suggested.
> > 
> > We could ignore this change for now if we don't expect the _OS object to
> > be used at all. But do we have any other way to check the AML code for
> > this? Would FWTS catch such obsolete cases?
> 
> How about just leaving it out? It's clearly not used for anything
> good, so I don't see the point in passing either Linux or "Microsoft
> Windows NT" here.

Do you mean defining it to NULL (so it ends up as NULL in
acpi_gbl_pre_defined_names) or removing "_OS_" entirely from that array?
I really can't tell what the implications are.

-- 
Catalin