linux-kernel - Re: [PATCH] video: fbdev: sis: init.c: Cleaning up redundant condition is always true

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Date:	Mon, 7 Jul 2014 10:57:09 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se>
Cc:	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Tomi Valkeinen <tomi.valkeinen@...com>,
	Jingoo Han <jg1.han@...sung.com>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	Mauro Carvalho Chehab <m.chehab@...sung.com>,
	"Chen, Gong" <gong.chen@...ux.intel.com>,
	linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] video: fbdev: sis: init.c:  Cleaning up redundant
 condition is always true

On Thu, Jul 03, 2014 at 11:15:21PM +0200, Rickard Strandqvist wrote:
> diff --git a/drivers/video/fbdev/sis/init.c b/drivers/video/fbdev/sis/init.c
> index bd40f5e..9e2dd96 100644
> --- a/drivers/video/fbdev/sis/init.c
> +++ b/drivers/video/fbdev/sis/init.c
> @@ -355,12 +355,12 @@ SiS_GetModeID(int VGAEngine, unsigned int VBFlags, int HDisplay, int VDisplay,
>  		}
>  		break;
>  	case 400:
> -		if((!(VBFlags & CRT1_LCDA)) || ((LCDwidth >= 800) && (LCDwidth >= 600))) {
> +		if ((!(VBFlags & CRT1_LCDA)) || (LCDwidth >= 600)) {


It might be that this was supposed to be:

		if((!(VBFlags & CRT1_LCDA)) || ((LCDwidth <= 800) && (LCDwidth >= 600))) {

But why would people write a range from high to low?  That's crazy
people who write backwards code...

The second condition was supposed to do *something* although it's
unclear what.  I would normally say that we should leave the static
checker warning here instead of guessing.  Perhaps add a comment like
/* fixme:  huh?  What's with this nonsense condition? */  But in this
case it's all dead code because LCDwidth is always zero and the code
hasn't changed since 2.6.12 so I don't care.

regards,
dan carpenter

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