[alsa-devel] [PATCH] ALSA: control: cage TLV_DB_RANGE_HEAD in kernel land because it was obsoleted

[Takashi Sakamoto]

(CCed to Mark Brown)

On Sep 26 2016 05:17, Takashi Iwai wrote:
> On Sat, 24 Sep 2016 12:28:23 +0200,
> Takashi Sakamoto wrote:
>>
>> In commit bf1d1c9b6179 ("ALSA: tlv: add DECLARE_TLV_DB_RANGE()"), the new
>> macro was added so that "dB range information can be specified without
>> having to count the items manually for TLV_DB_RANGE_HEAD()". In short,
>> TLV_DB_RANGE_HEAD macro was obsoleted.
>>
>> In commit 46e860f76804 ("ALSA: rename TLV-related macros so that they're
>> friendly to user applications"), TLV-related macros are exposed for
>> applications in user land to get content of data structured by
>> Type/Length/Value shape. The commit managed to expose TLV-related macros
>> as many as possible, while obsoleted TLV_DB_RANGE_HEAD() was included to
>> the list of exposed macros.
>>
>> This situation brings some confusions to application developers because
>> they might think all exposed macros have their own purpose and useful for
>> applications.
>>
>> For the reason, this commit moves TLV_DB_RANGE_HEAD macro from UAPI header
>> to a header for kernel land, again. The above commit is done within the
>> same development period for kernel 4.9, thus not published yet. This
>> commit might certainly brings no confusions to user land.
>>
>> Reference: commit bf1d1c9b6179 ("ALSA: tlv: add DECLARE_TLV_DB_RANGE()")
>> Reference: commit 46e860f76804 ("ALSA: rename TLV-related macros so that they're friendly to user applications")
>> Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
> 
> Fair enough, applied now.  Thanks.

And I think it better to replace usage of this macro with
SNDRV_CTL_TLVD_DECLARE_DB_RANGE. In your linux-next tree, addressed
macro is used by three drivers:

$ git grep TLV_DB_RANGE_HEAD
include/sound/tlv.h:#define TLV_DB_RANGE_HEAD
SNDRV_CTL_TLVD_DB_RANGE_HEAD
sound/soc/codecs/max9867.c:     TLV_DB_RANGE_HEAD(2),
sound/soc/codecs/rt5616.c:      TLV_DB_RANGE_HEAD(7),
sound/soc/codecs/wm8960.c:      TLV_DB_RANGE_HEAD(2),

How do you think about doing it in time of kernel 4.9 merge window?


Regards

Takashi Sakamoto

>> ---
>>  include/sound/tlv.h      | 9 ++++++++-
>>  include/uapi/sound/tlv.h | 3 ---
>>  2 files changed, 8 insertions(+), 4 deletions(-)
>>
>> diff --git a/include/sound/tlv.h b/include/sound/tlv.h
>> index 6e2e773..3677ebb 100644
>> --- a/include/sound/tlv.h
>> +++ b/include/sound/tlv.h
>> @@ -46,8 +46,15 @@
>>  
>>  #define TLV_DB_RANGE_ITEM		SNDRV_CTL_TLVD_DB_RANGE_ITEM
>>  #define DECLARE_TLV_DB_RANGE		SNDRV_CTL_TLVD_DECLARE_DB_RANGE
>> -#define TLV_DB_RANGE_HEAD		SNDRV_CTL_TLVD_DB_RANGE_HEAD
>>  
>>  #define TLV_DB_GAIN_MUTE		SNDRV_CTL_TLVD_DB_GAIN_MUTE
>>  
>> +/*
>> + * The below assumes that each item TLV is 4 words like DB_SCALE or LINEAR.
>> + * This is an old fasion and obsoleted by commit bf1d1c9b6179("ALSA: tlv: add
>> + * DECLARE_TLV_DB_RANGE()").
>> + */
>> +#define TLV_DB_RANGE_HEAD(num) \
>> +	SNDRV_CTL_TLVT_DB_RANGE, 6 * (num) * sizeof(unsigned int)
>> +
>>  #endif /* __SOUND_TLV_H */
>> diff --git a/include/uapi/sound/tlv.h b/include/uapi/sound/tlv.h
>> index f3c198f..b4df440 100644
>> --- a/include/uapi/sound/tlv.h
>> +++ b/include/uapi/sound/tlv.h
>> @@ -94,9 +94,6 @@
>>  	unsigned int name[] = { \
>>  		SNDRV_CTL_TLVD_DB_RANGE_ITEM(__VA_ARGS__) \
>>  	}
>> -/* The below assumes that each item TLV is 4 words like DB_SCALE or LINEAR */
>> -#define SNDRV_CTL_TLVD_DB_RANGE_HEAD(num) \
>> -	SNDRV_CTL_TLVT_DB_RANGE, 6 * (num) * sizeof(unsigned int)
>>  
>>  #define SNDRV_CTL_TLVD_DB_GAIN_MUTE	-9999999
>>  
>> -- 
>> 2.7.4