From mboxrd@z Thu Jan  1 00:00:00 1970
From: daniel@caiaq.de (Daniel Mack)
Date: Fri, 13 Nov 2009 00:17:03 +0100
Subject: [PATCH] ARM: Prefix revision number in /proc/cpuinfo
In-Reply-To: <20091112221307.GC12308@n2100.arm.linux.org.uk>
References: <1258034287-4533-1-git-send-email-daniel@caiaq.de>
	<20091112215201.GA12308@n2100.arm.linux.org.uk>
	<20091112220314.GS14091@buzzloop.caiaq.de>
	<20091112221307.GC12308@n2100.arm.linux.org.uk>
Message-ID: <20091112231703.GT14091@buzzloop.caiaq.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Thu, Nov 12, 2009 at 10:13:07PM +0000, Russell King - ARM Linux wrote:
> On Thu, Nov 12, 2009 at 11:03:14PM +0100, Daniel Mack wrote:
> > On Thu, Nov 12, 2009 at 09:52:01PM +0000, Russell King - ARM Linux wrote:
> > > On Thu, Nov 12, 2009 at 02:58:07PM +0100, Daniel Mack wrote:
> > > > The revision field in /proc/cpuinfo is reported as hex number, so it
> > > > should have a '0x' prefix to make that clear. Otherwise, parsers
> > > > will take it as decimal number unless it contains a letter.
> > > 
> > > So what you're doing is possibly breaking existing parsers (which
> > > probably already assume it is hex) to fix buggy parsers?
> > 
> > I wouldn't call that fixing a buggy parser. On my board, the revision is
> > 0x101 which was parsed as 101. You can't know it is in hex unless you
> > look at the sources.
> 
> However, we export lots of stuff from the kernel in hex without an '0x'
> prefix.
> 
> The biggest point here, though, is that the field is already present and
> has been used, created about 10 years ago for NetWinder stuff.  So we've
> about 10 years of history of it being there.  Adding the '0x' prefix may
> break existing parsers, which is a good enough reason not to change it.
> 
> Moreover, if you try to parse the field using strtoul, you'll generally
> end up with it being interpreted as an _octal_ number due to the leading
> zeros - which should be enough of a hint that it isn't a decimal number.
> 
> If you really feel strongly about it, then the only portable way of fixing
> it would be to create a new entry in the file with the '0x' prefix.

Hmm, no. I think we will just force the parser to hex then. Not that
important. It's just that all other fields in /proc/cpuinfo which are in
hex _are_ prefixed indeed, but I see the risk of breaking existing
parsers, so let's keep it the way it is.

Thanks,
Daniel