linux-kernel - Re: [PATCH v3 7/8] video: xilinxfb: Fix sparse warnings

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Message-ID: <4930944.aMQtpv2nTI@wuerfel>
Date:	Fri, 31 May 2013 17:29:50 +0200
From:	Arnd Bergmann <arnd@...db.de>
To:	Timur Tabi <timur@...i.org>
Cc:	monstr@...str.eu, Michal Simek <michal.simek@...inx.com>,
	linux-kernel@...r.kernel.org,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Tomi Valkeinen <tomi.valkeinen@...com>,
	linux-fbdev@...r.kernel.org
Subject: Re: [PATCH v3 7/8] video: xilinxfb: Fix sparse warnings

On Friday 31 May 2013 10:06:43 Timur Tabi wrote:
> On 05/31/2013 09:56 AM, Arnd Bergmann wrote:
> > Yes, unfortunately, this is what all other frame buffer drivers do
> > at the moment. It is technically not correct, but most architectures
> > are able to call readl/writel on regular memory, or dereference
> > __iomem tokens, so we often get away with it. It's probably not
> > worth fixing it in the fbdev code base as that would be a huge
> > change, and people are migrating to DRM/KMS.
> 
> But why bother fixing this bug if it just makes things worse?  Sparse is
> supposed to warn us about bad code.  This patch doesn't fix the bug, it
> just masks the warnings!

Yes, good point. It's probably best cast the ioremap() output to
a regular pointer here, as that is actually just uncached RAM,
not an MMIO register.

	Arnd
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