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ALSA: usb-audio - Add volume range check and warn if it too big 

Signed-off-by: Alexey Fisher <bug-track@fisher-privat.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
hifive-unleashed-5.1
Alexey Fisher 2011-03-10 14:53:38 +01:00 committed by Takashi Iwai
parent 848669da3a
commit 80acefff3b
1 changed files with 16 additions and 0 deletions
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16
sound/usb/mixer.c
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@ -987,6 +987,7 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
struct snd_kcontrol *kctl;
struct usb_mixer_elem_info *cval;
const struct usbmix_name_map *map;
unsigned int range;
control++; /* change from zero-based to 1-based value */
@ -1136,6 +1137,21 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
}
range = (cval->max - cval->min) / cval->res;
/* Are there devices with volume range more than 255? I use a bit more
* to be sure. 384 is a resolution magic number found on Logitech
* devices. It will definitively catch all buggy Logitech devices.
*/
if (range > 384) {
snd_printk(KERN_WARNING "usb_audio: Warning! Unlikely big "
"volume range (=%u), cval->res is probably wrong.",
range);
snd_printk(KERN_WARNING "usb_audio: [%d] FU [%s] ch = %d, "
"val = %d/%d/%d", cval->id,
kctl->id.name, cval->channels,
cval->min, cval->max, cval->res);
}
snd_printdd(KERN_INFO "[%d] FU [%s] ch = %d, val = %d/%d/%d\n",
cval->id, kctl->id.name, cval->channels, cval->min, cval->max, cval->res);
add_control_to_empty(state, kctl);