[alsa-devel] [PATCH] test: fix comment about first two fields of TLV data payload

[Takashi Sakamoto]

On Aug 30 2016 16:24, Clemens Ladisch wrote:
> In the kernel, you could use the macros from include/sound/tlv.h.
> 
> Either copy them into your test program, and use them directly:
> 
> 	/* 4 words: */
> 	DECLARE_TLV_DB_MINMAX(orig, -60, +60);
> 	/* container with only one subitem; 8 words: */
> 	DECLARE_TLV_CONTAINER(orig_container,
> 		TLV_ITEM(SNDRV_CTL_TLVT_CHMAP_FIXED,
> 			 SNDRV_CHMAP_FL, SNDRV_CHMAP_FR, SNDRV_CHMAP_FC, SNDRV_CHMAP_LFE)
> 	);
> 
> or create the values by hand:
> 
> 	orig[0] = SNDRV_CTL_TLVT_DB_MINMAX;
> 	orig[1] = 2 * sizeof(*orig);
> 	orig[2] = -60;
> 	orig[3] = +60;
> 
> 	orig_container[0] = SNDRV_CTL_TLVT_CONTAINER;
> 	orig_container[1] = 6 * sizeof(*orig_container);
> 		orig_container[2] = SNDRV_CTL_TLVT_CHMAP_FIXED;
> 		orig_container[3] = 4 * sizeof(*orig_container);
> 		orig_container[4] = SNDRV_CHMAP_FL
> 		orig_container[5] = SNDRV_CHMAP_FR;
> 		orig_container[6] = SNDRV_CHMAP_FC;
> 		orig_container[7] = SNDRV_CHMAP_LFE;

Mmm. For user-defined control element sets, these macros should be in UAPI.

SNDRV_CTL_IOCTL_ELEM_ADD was really long abandoned...


Thanks

Takashi Sakamoto