linux-kernel - Re: [v4l-dvb-maintainer] [PATCH] dvb: usb vendor_ids/product_ids are _

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Date:	Fri, 14 Nov 2008 14:25:57 -0500
From:	"Devin Heitmueller" <devin.heitmueller@...il.com>
To:	"Harvey Harrison" <harvey.harrison@...il.com>
Cc:	"Michael Krufky" <mkrufky@...uxtv.org>,
	"Mauro Carvalho Chehab" <mchehab@...radead.org>,
	v4l-maintainer <v4l-dvb-maintainer@...uxtv.org>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [v4l-dvb-maintainer] [PATCH] dvb: usb vendor_ids/product_ids are __le16

On Fri, Nov 14, 2008 at 2:20 PM, Harvey Harrison
<harvey.harrison@...il.com> wrote:
> On Fri, 2008-11-14 at 14:15 -0500, Michael Krufky wrote:
>> On Fri, Nov 14, 2008 at 2:07 PM, Harvey Harrison
>> <harvey.harrison@...il.com> wrote:
>> > On Fri, 2008-11-14 at 14:05 -0500, Michael Krufky wrote:
>> >> Wouldn't it be nicer to just switch on
>> >> cpu_to_le16(udev->descriptor.idVendor) ?  This would be a 1-line change,
>> >> compile to a smaller footprint, and be easier to read.
>> >>
>> >> Personally, I prefer to try to avoid duplicating code in places where a
>> >> single operation may occur centrally.
>> >
>> > On a little-endian arch it makes no difference obviously, but on a
>> > big-endian arch it's the difference between compile-time and runtime
>> > byteswapping.
>> >
>>
>> Its not my driver, but I think that doing the operation on the switch
>> is prettier than doing it on each case statement.  Also, it would
>> avoid future bugs, if somebody decides to add new cases to the switch
>> block.
>
> The alternative is to define the vendor ids as little-endian in the headers
> then you don't need the endian swap in the switch or the case, but that would
> require looking at the other uses first....or gently encourage more people to run sparse ;-)
>
> Harvey

Harvey,

If I may offer my opinion, this is not remotely performance-critical
code.  That said, I would favor on the side of
maintainability/reliability in this case, and mkrufky's approach seems
to be better on both accounts.

Regards,

Devin

-- 
Devin J. Heitmueller
http://www.devinheitmueller.com
AIM: devinheitmueller
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