2014-07-03 21:14:10

by Rickard Strandqvist

Subject: [PATCH] video: fbdev: sis: init.c: Cleaning up redundant condition is always true

Removal of a redundant condition that is always true

This was found using a static code analysis program called cppcheck

Signed-off-by: Rickard Strandqvist <[email protected]>
---
drivers/video/fbdev/sis/init.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

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)) {
if(VDisplay == 300) ModeIndex = ModeIndex_400x300[Depth];
}
break;
case 512:
- if((!(VBFlags & CRT1_LCDA)) || ((LCDwidth >= 1024) && (LCDwidth >= 768))) {
+ if ((!(VBFlags & CRT1_LCDA)) || (LCDwidth >= 768)) {
if(VDisplay == 384) ModeIndex = ModeIndex_512x384[Depth];
}
break;
--
1.7.10.4

2014-07-07 07:57:31

by Dan Carpenter

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

2014-07-07 09:28:47

by Noralf Trønnes

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

Den 07.07.2014 09:57, skrev Dan Carpenter:
> 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 numbers 800x600 (1024x768) indicate that LCDheight is meant to be used:
if((!(VBFlags & CRT1_LCDA)) || ((LCDwidth >= 800) &&
(LCDheight >= 600))) {

regards,
Noralf Tronnes

2014-07-07 20:36:40

by Rickard Strandqvist

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

2014-07-07 11:23 GMT+02:00 Noralf Tronnes <[email protected]>:
> Den 07.07.2014 09:57, skrev Dan Carpenter:
>
>> 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 numbers 800x600 (1024x768) indicate that LCDheight is meant to be used:
> if((!(VBFlags & CRT1_LCDA)) || ((LCDwidth >= 800) &&
> (LCDheight >= 600))) {
>
> regards,
> Noralf Tronnes

Hi

Nice, this is what is the point of fix this type of minor errors.
Sometimes you can find something more serious :)

New patch on the way!

Kind regards
Rickard Strandqvist