alsa: correct assumptions about channels an element lacks

If an element does not control some channels assume they are 0dB in
comparison to the other elements, i.e. do not influence the volume at
all. Previously we were assuming they were as high as the highest of the
channels we do control.

diff --git a/src/modules/alsa/alsa-mixer.c b/src/modules/alsa/alsa-mixer.c
index 685169b..8d54d58 100644 (file)
--- a/src/modules/alsa/alsa-mixer.c
+++ b/src/modules/alsa/alsa-mixer.c
@@ -479,7 +479,6 @@ static int element_get_volume(pa_alsa_element *e, snd_mixer_t *m, const pa_chann
     snd_mixer_elem_t *me;
     snd_mixer_selem_channel_id_t c;
     pa_channel_position_mask_t mask = 0;
-    pa_volume_t max_channel_volume = PA_VOLUME_MUTED;
     unsigned k;
 
     pa_assert(m);
@@ -546,9 +545,6 @@ static int element_get_volume(pa_alsa_element *e, snd_mixer_t *m, const pa_chann
             f = from_alsa_volume(value, e->min_volume, e->max_volume);
         }
 
-        if (f > max_channel_volume)
-            max_channel_volume = f;
-
         for (k = 0; k < cm->channels; k++)
             if (e->masks[c][e->n_channels-1] & PA_CHANNEL_POSITION_MASK(cm->map[k]))
                 if (v->values[k] < f)
@@ -559,7 +555,7 @@ static int element_get_volume(pa_alsa_element *e, snd_mixer_t *m, const pa_chann
 
     for (k = 0; k < cm->channels; k++)
         if (!(mask & PA_CHANNEL_POSITION_MASK(cm->map[k])))
-            v->values[k] = max_channel_volume;
+            v->values[k] = PA_VOLUME_NORM;
 
     return 0;
 }
@@ -681,7 +677,6 @@ static int element_set_volume(pa_alsa_element *e, snd_mixer_t *m, const pa_chann
     snd_mixer_elem_t *me;
     snd_mixer_selem_channel_id_t c;
     pa_channel_position_mask_t mask = 0;
-    pa_volume_t max_channel_volume = PA_VOLUME_MUTED;
     unsigned k;
 
     pa_assert(m);
@@ -771,9 +766,6 @@ static int element_set_volume(pa_alsa_element *e, snd_mixer_t *m, const pa_chann
             f = from_alsa_volume(value, e->min_volume, e->max_volume);
         }
 
-        if (f > max_channel_volume)
-            max_channel_volume = f;
-
         for (k = 0; k < cm->channels; k++)
             if (e->masks[c][e->n_channels-1] & PA_CHANNEL_POSITION_MASK(cm->map[k]))
                 if (rv.values[k] < f)
@@ -784,7 +776,7 @@ static int element_set_volume(pa_alsa_element *e, snd_mixer_t *m, const pa_chann
 
     for (k = 0; k < cm->channels; k++)
         if (!(mask & PA_CHANNEL_POSITION_MASK(cm->map[k])))
-            rv.values[k] = max_channel_volume;
+            rv.values[k] = PA_VOLUME_NORM;
 
     *v = rv;
     return 0;