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Commit 085f3065 authored by Takashi Iwai's avatar Takashi Iwai
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ALSA: Add new TLV types for dBwith min/max 



Add new types for TLV dB scale specified with min/max values instead
of min/step since the resolution can't match always with the one
a device provides.  For example, usb audio devices give 1/256 dB
resolution while ALSA TLV is based on 1/100 dB resolution.
The new min/max types have less problems because the possible
rounding error happens only at min/max.

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 07a2039b

include/sound/tlv.h

+14 −0
Original line number Diff line number Diff line
@@ -35,6 +35,8 @@ 
#define SNDRV_CTL_TLVT_DB_SCALE	1       /* dB scale */

#define SNDRV_CTL_TLVT_DB_LINEAR 2	/* linear volume */

#define SNDRV_CTL_TLVT_DB_RANGE 3	/* dB range container */

#define SNDRV_CTL_TLVT_DB_MINMAX 4	/* dB scale with min/max */

#define SNDRV_CTL_TLVT_DB_MINMAX_MUTE 5	/* dB scale with min/max with mute */



#define TLV_DB_SCALE_ITEM(min, step, mute)			\

	SNDRV_CTL_TLVT_DB_SCALE, 2 * sizeof(unsigned int),	\
@@ -42,6 +44,18 @@ 
#define DECLARE_TLV_DB_SCALE(name, min, step, mute) \

	unsigned int name[] = { TLV_DB_SCALE_ITEM(min, step, mute) }



/* dB scale specified with min/max values instead of step */

#define TLV_DB_MINMAX_ITEM(min_dB, max_dB)			\

	SNDRV_CTL_TLVT_DB_MINMAX, 2 * sizeof(unsigned int),	\

	(min_dB), (max_dB)

#define TLV_DB_MINMAX_MUTE_ITEM(min_dB, max_dB)			\

	SNDRV_CTL_TLVT_DB_MINMAX_MUTE, 2 * sizeof(unsigned int),	\

	(min_dB), (max_dB)

#define DECLARE_TLV_DB_MINMAX(name, min_dB, max_dB) \

	unsigned int name[] = { TLV_DB_MINMAX_ITEM(min_dB, max_dB) }

#define DECLARE_TLV_DB_MINMAX_MUTE(name, min_dB, max_dB) \

	unsigned int name[] = { TLV_DB_MINMAX_MUTE_ITEM(min_dB, max_dB) }



/* linear volume between min_dB and max_dB (.01dB unit) */

#define TLV_DB_LINEAR_ITEM(min_dB, max_dB)		    \

	SNDRV_CTL_TLVT_DB_LINEAR, 2 * sizeof(unsigned int), \

sound/core/vmaster.c

+6 −2
Original line number Diff line number Diff line
@@ -353,7 +353,8 @@ static void master_free(struct snd_kcontrol *kcontrol) 
 *

 * The optional argument @tlv can be used to specify the TLV information

 * for dB scale of the master control.  It should be a single element

 * with #SNDRV_CTL_TLVT_DB_SCALE type, and should be the max 0dB.

 * with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or

 * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.

 */

struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,

						 const unsigned int *tlv)
@@ -384,7 +385,10 @@ struct snd_kcontrol *snd_ctl_make_virtual_master(char *name, 
	kctl->private_free = master_free;



	/* additional (constant) TLV read */

	if (tlv && tlv[0] == SNDRV_CTL_TLVT_DB_SCALE) {

	if (tlv &&

	    (tlv[0] == SNDRV_CTL_TLVT_DB_SCALE ||

	     tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX ||

	     tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX_MUTE)) {

		kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;

		memcpy(master->tlv, tlv, sizeof(master->tlv));

		kctl->tlv.p = master->tlv;