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Improve mapping of relative to absolute volume.

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I added bounds checking to the patch and cg improved
the formular.

Submitted by:	Andriy Gapon <avg@icyb.net.ua>
PR:		kern/65485
Approved by:	cg
Reviewed by:	imp, rwatson, le
This commit is contained in:
Josef El-Rayes 2004-06-14 15:01:16 +00:00
parent 939fca9bea
commit 134896e1fc
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=130472
1 changed files with 15 additions and 2 deletions
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17
sys/dev/sound/isa/sb16.c
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@ -330,6 +330,19 @@ sb16mix_init(struct snd_mixer *m)
return 0;
}
static int
rel2abs_volume(int x, int max)
{
int temp;
temp = ((x * max) + 50) / 100;
if (temp > max)
temp = max;
else if (temp < 0)
temp = 0;
return (temp);
}
static int
sb16mix_set(struct snd_mixer *m, unsigned dev, unsigned left, unsigned right)
{
@ -340,8 +353,8 @@ sb16mix_set(struct snd_mixer *m, unsigned dev, unsigned left, unsigned right)
e = &sb16_mixtab[dev];
max = (1 << e->bits) - 1;
left = (left * max) / 100;
right = (right * max) / 100;
left = rel2abs_volume(left, max);
right = rel2abs_volume(right, max);
sb_setmixer(sb, e->reg, left << e->ofs);
if (e->stereo)