Subject: Re: [PATCH] leds: Fix locking for WM8350
From: Richard Purdie <rpurdie@rpsys.net>
To: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Pavel Machek <pavel@suse.cz>, linux-kernel@vger.kernel.org
In-Reply-To: <20081115191414.GA12907@opensource.wolfsonmicro.com>
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	 <20081115185119.GA19900@elf.ucw.cz>
	 <20081115191414.GA12907@opensource.wolfsonmicro.com>
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Date: Mon, 17 Nov 2008 15:33:15 +0000
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On Sat, 2008-11-15 at 19:14 +0000, Mark Brown wrote:
> On Sat, Nov 15, 2008 at 07:51:20PM +0100, Pavel Machek wrote:
> > On Sat 2008-11-15 17:50:50, Mark Brown wrote:
> 
> > > Yes, that'd be safer though I'd be surprised to see systems that could
> > > trigger it.
> 
> > Yes, they are uncommon. They exist; SPARC, IIRC. Plus you need
> 
> Exceptionally uncommon with the systems the WM8350 gets used with -
> it's a primary PMIC for mobile devices so anything other than
> uniprocessor ARM would be surprising.
> 
> > barriers on anything SMP... Just use atomic_t.
> 
> I was intending to do so next time I spin the patch.  Andrew had some
> other comments and I don't have any test systems when I'm not in the
> office anyway.

I've not looked in detail at the code but it looks like a maximum of a
32 bit value where you don't actually care which write succeeds as long
as it takes one of the values written? I don't see why that particular
variable needs any locking or to be atomic?

Cheers,

Richard

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