From: Michael Buesch <mb@bu3sch.de>
To: Russell King <rmk+lkml@arm.linux.org.uk>
Subject: Re: [RFC] [PATCH] Fix b43 driver build for arm
Date: Mon, 18 Feb 2008 23:43:12 +0100
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Cc: Gordon Farquharson <gordonfarquharson@gmail.com>,
       linux-kernel@vger.kernel.org, linville@tuxdriver.com,
       stefano.brivio@polimi.it
References: <97a0a9ac0802181403ja79c32v864b093414b2755@mail.gmail.com> <200802182324.45267.mb@bu3sch.de> <20080218223410.GD23181@flint.arm.linux.org.uk>
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On Monday 18 February 2008 23:34:10 Russell King wrote:
> On Mon, Feb 18, 2008 at 11:24:44PM +0100, Michael Buesch wrote:
> > On Monday 18 February 2008 23:13:24 Russell King wrote:
> > > On Mon, Feb 18, 2008 at 11:08:56PM +0100, Michael Buesch wrote:
> > > > On Monday 18 February 2008 23:03:10 Gordon Farquharson wrote:
> > > > > The b43 driver in 2.6.25-rc[12] fails to build for arm on an x86_64
> > > > > box using a cross-compiler:
> > > > > 
> > > > > FATAL: drivers/net/wireless/b43/b43: sizeof(struct ssb_device_id)=6 is
> > > > > not a modulo of the size of section __mod_ssb_device_table=64.
> > > > > Fix definition of struct ssb_device_id in mod_devicetable.h
> > > > 
> > > > Why does ARM have this special requirement and what is it about?
> > > 
> > > Because ARM is a 32 bit architecture.
> > 
> > Ehm, I didn't see this warning on any other architecture nor did we
> > have _any_ problem with it on any other architecture.
> > This code runs fine on x86_32, x86_64, powerpc and mips, at least.
> 
> Well, don't expect this driver to work until you fix your broken
> assumptions about alignment requirements.

Mr King, I'm not an idiot!

Can you _please_ explain what makes ARM so special here?
Why can't we have an array of this structure on ARM?

struct ssb_device_id {
       __u16   vendor;
       __u16   coreid;
       __u8    revision;
};

I will not apply any patches that I don't understand.
Why doesn't the compiler handle this? What's special? Can you please explain?

-- 
Greetings Michael.
--
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