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-rw-r--r--sound/usb/usbmixer.c37
1 files changed, 34 insertions, 3 deletions
diff --git a/sound/usb/usbmixer.c b/sound/usb/usbmixer.c
index 8d08b34a1cb..ce86283ee0f 100644
--- a/sound/usb/usbmixer.c
+++ b/sound/usb/usbmixer.c
@@ -306,8 +306,8 @@ static int get_relative_value(struct usb_mixer_elem_info *cval, int val)
cval->res = 1;
if (val < cval->min)
return 0;
- else if (val > cval->max)
- return (cval->max - cval->min) / cval->res;
+ else if (val >= cval->max)
+ return (cval->max - cval->min + cval->res - 1) / cval->res;
else
return (val - cval->min) / cval->res;
}
@@ -670,6 +670,36 @@ static int get_min_max(struct usb_mixer_elem_info *cval, int default_min)
}
if (cval->res == 0)
cval->res = 1;
+
+ /* Additional checks for the proper resolution
+ *
+ * Some devices report smaller resolutions than actually
+ * reacting. They don't return errors but simply clip
+ * to the lower aligned value.
+ */
+ if (cval->min + cval->res < cval->max) {
+ int last_valid_res = cval->res;
+ int saved, test, check;
+ get_cur_mix_value(cval, minchn, &saved);
+ for (;;) {
+ test = saved;
+ if (test < cval->max)
+ test += cval->res;
+ else
+ test -= cval->res;
+ if (test < cval->min || test > cval->max ||
+ set_cur_mix_value(cval, minchn, test) ||
+ get_cur_mix_value(cval, minchn, &check)) {
+ cval->res = last_valid_res;
+ break;
+ }
+ if (test == check)
+ break;
+ cval->res *= 2;
+ }
+ set_cur_mix_value(cval, minchn, saved);
+ }
+
cval->initialized = 1;
}
return 0;
@@ -695,7 +725,8 @@ static int mixer_ctl_feature_info(struct snd_kcontrol *kcontrol, struct snd_ctl_
if (! cval->initialized)
get_min_max(cval, 0);
uinfo->value.integer.min = 0;
- uinfo->value.integer.max = (cval->max - cval->min) / cval->res;
+ uinfo->value.integer.max =
+ (cval->max - cval->min + cval->res - 1) / cval->res;
}
return 0;
}