ALSA: Add comment for control TLV API

Userspace is not meant to have to handle all strange dB ranges,
so add a specification comment.

Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
David Henningsson 2013-05-08 15:33:11 +02:00 committed by Takashi Iwai
parent 17df3f5565
commit d24f5a9ad9

View File

@ -74,7 +74,11 @@
#define DECLARE_TLV_DB_LINEAR(name, min_dB, max_dB) \
unsigned int name[] = { TLV_DB_LINEAR_ITEM(min_dB, max_dB) }
/* dB range container */
/* dB range container:
* Items in dB range container must be ordered by their values and by their
* dB values. This implies that larger values must correspond with larger
* dB values (which is also required for all other mixer controls).
*/
/* Each item is: <min> <max> <TLV> */
#define TLV_DB_RANGE_ITEM(...) \
TLV_ITEM(SNDRV_CTL_TLVT_DB_RANGE, __VA_ARGS__)