From mboxrd@z Thu Jan  1 00:00:00 1970
From: catalin.marinas@arm.com (Catalin Marinas)
Date: Tue, 6 Jan 2015 11:20:01 +0000
Subject: [PATCH v5 18/18] Documentation: ACPI for ARM64
In-Reply-To: <1797489.PjmKzBFdQA@wuerfel>
References: <1413553034-20956-1-git-send-email-hanjun.guo@linaro.org>
 <54A28B22.7090305@linaro.org>
 <20150105131302.GB14967@e104818-lin.cambridge.arm.com>
 <1797489.PjmKzBFdQA@wuerfel>
Message-ID: <20150106112000.GA8829@e104818-lin.cambridge.arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Jan 05, 2015 at 08:16:30PM +0000, Arnd Bergmann wrote:
> On Monday 05 January 2015 13:13:02 Catalin Marinas wrote:
> > > since passing no DT tables to OS but
> > > acpi=force is missing is a corner case, we can do a follow up patch to
> > > fix that, does it make sense?
> > 
> > Not entirely. Why would no dtb and no acpi=force be a corner case? I
> > thought this should be the default when only ACPI tables are passed, no
> > need for an additional acpi=force argument.
> 
> We don't really support the case of only ACPI tables for now. The expectation
> is that you always have working DT support, at least for the next few years
> as ACPI features are ramping up, and without acpi=force it should not try
> to use ACPI at all.

So if both DT and ACPI are present, just use DT unless acpi=force is
passed. So far I think we agree but what I want to avoid is always
mandating acpi=force even when the DT tables are missing (in the long
run).

Now, what's preventing a vendor firmware from providing only ACPI
tables? Do we enforce it in some way (arm-acpi.txt, kernel warning etc.)
that both DT and ACPI are supported, or at least that dts files are
merged in the kernel first?

-- 
Catalin