svn commit: r333801 - head/sys/contrib/dev/ath/ath_hal/ar9300

[Sean Bruno]

On 05/18/18 11:29, Ian Lepore wrote:
> On Fri, 2018-05-18 at 17:23 +0000, Sean Bruno wrote:
>> Author: sbruno
>> Date: Fri May 18 17:23:23 2018
>> New Revision: 333801
>> URL: https://svnweb.freebsd.org/changeset/base/333801
>>
>> Log:
>>   Quiesce a couple pages of clang warnings with a cast.  Duplicates
>>   linux maintainer commit:
>>   
>>   https://github.com/torvalds/linux/commit/627871b71c89a6ec12fbed75063f238e0c7127b2#diff-8c6ddb4c3ad69a6fb9f289475821db56
>>   
>>   ar9300template_aphrodite.h:575:40: warning: implicit conversion from 'int'
>>     to 'u_int8_t' (aka 'unsigned char') changes value from 3495 to 167
>>     [-Wconstant-conversion]
>>               /* Data[8].ctl_edges[7].bChannel*/FREQ2FBIN(5795, 0)}
>>                                                 ^~~~~~~~~~~~~~~~~~
>>   ar9300eep.h:142:41: note: expanded from macro 'FREQ2FBIN'
>>       (((y) == HAL_FREQ_BAND_2GHZ) ? ((x) - 2300) : (((x) - 4800) / 5))
>>   
>>   Reviewed by:	imp
>>   MFC after:	1 week
>>   Differential Revision:	https://reviews.freebsd.org/D15476
>>
>> Modified:
>>   head/sys/contrib/dev/ath/ath_hal/ar9300/ar9300eep.h
>>
>> Modified: head/sys/contrib/dev/ath/ath_hal/ar9300/ar9300eep.h
>> ==============================================================================
>> --- head/sys/contrib/dev/ath/ath_hal/ar9300/ar9300eep.h	Fri May 18 17:07:59 2018	(r333800)
>> +++ head/sys/contrib/dev/ath/ath_hal/ar9300/ar9300eep.h	Fri May 18 17:23:23 2018	(r333801)
>> @@ -139,7 +139,7 @@ enum Ar9300EepromTemplate
>>  #define OSPREY_CUSTOMER_DATA_SIZE    20
>>  
>>  #define FREQ2FBIN(x,y) \
>> -    (((y) == HAL_FREQ_BAND_2GHZ) ? ((x) - 2300) : (((x) - 4800) / 5))
>> +    (u_int8_t)(((y) == HAL_FREQ_BAND_2GHZ) ? ((x) - 2300) : (((x) - 4800) / 5))
>>  #define FBIN2FREQ(x,y) \
>>      (((y) == HAL_FREQ_BAND_2GHZ) ? (2300 + x) : (4800 + 5 * x))
>>  #define OSPREY_MAX_CHAINS            3
>>
> 
> How can this change possibly be correct? All the values involved are
> compile-time constants, the compiler did the math and tells you the
> result is 3495. Cast or not, that value is never going to fit into a
> uint8_t. Sure this supresses the warning, but what about actually
> fixing the overflow?
> 
> -- Ian
> 
> 


An excellent question all around.  It appears that the maintainer at
Qualcom acked the linux commit, so I'm not sure how to interpret all of
this.

sean

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