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Date: Fri, 10 Sep 2010 12:21:35 -0600
From: Grant Likely <grant.likely@secretlab.ca>
To: Ingo Molnar <mingo@elte.hu>
Cc: Andres Salomon <dilinger@queued.net>, devicetree-discuss@lists.ozlabs.org,
        x86@kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
        Mitch Bradley <wmb@laptop.org>, linux-kernel@vger.kernel.org,
        Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Subject: Re: [PATCH 2/2] x86: of: define irq functions to allow
 drivers/of/* to build on x86
Message-ID: <20100910182135.GG11284@angua.secretlab.ca>
References: <20100910060151.6613e9c3@debxo>
 <20100910172538.GC11284@angua.secretlab.ca>
 <20100910181458.GA7243@elte.hu>
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On Fri, Sep 10, 2010 at 08:14:58PM +0200, Ingo Molnar wrote:
> 
> * Grant Likely <grant.likely@secretlab.ca> wrote:
> 
> > On Fri, Sep 10, 2010 at 06:01:51AM -0700, Andres Salomon wrote:
> > > 
> > >  - Define a stub irq_create_of_mapping for x86 as a stop-gap solution until
> > >    drivers/of/irq is further along.
> > >  - Define irq_dispose_mapping for x86 to appease of_i2c.c
> > > 
> > > Signed-off-by: Andres Salomon <dilinger@queued.net>
> > 
> > Applied to my test-devicetree branch.  I'll need an ack from the x86 
> > maintainers before I put it into my -next branch.
> 
> The purpose of the patch is not clear to me. What does it do and why? 

It allows CONFIG_OF to be enabled on x86 without a build failure.

> The changelog says it's a stopgap measure - what exactly is the long 
> term plan and how long will it take?

It is a stop gap because it performs a trivial direct map of an IRQ
number in the device tree data structure to a Linux irq number.  This
works for a single IRQ controller, but falls apart when cascaded
controller are described in the device tree.  The long term plan is to
have the drivers/of/ code handling the mapping intelligently like
powerpc currently does.

g.