ALSA: usb-audio: scarlett2: Fix data_mutex lock

The private->vol_updated flag was being checked outside of the
mutex_lock/unlock() of private->data_mutex leading to the volume data
being fetched twice from the device unnecessarily or old volume data
being returned.

Update scarlett2_*_ctl_get() and include the private->vol_updated flag
check inside the critical region.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/20210620164643.GA9216@m.b4.vu
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Geoffrey D. Bennett 2021-06-21 02:16:43 +09:30 committed by Takashi Iwai
parent 3eeb2a19db
commit 9b5ddea9ce

View File

@ -1153,11 +1153,10 @@ static int scarlett2_master_volume_ctl_get(struct snd_kcontrol *kctl,
struct usb_mixer_interface *mixer = elem->head.mixer;
struct scarlett2_data *private = mixer->private_data;
if (private->vol_updated) {
mutex_lock(&private->data_mutex);
if (private->vol_updated)
scarlett2_update_volumes(mixer);
mutex_unlock(&private->data_mutex);
}
ucontrol->value.integer.value[0] = private->master_vol;
return 0;
@ -1171,11 +1170,10 @@ static int scarlett2_volume_ctl_get(struct snd_kcontrol *kctl,
struct scarlett2_data *private = mixer->private_data;
int index = elem->control;
if (private->vol_updated) {
mutex_lock(&private->data_mutex);
if (private->vol_updated)
scarlett2_update_volumes(mixer);
mutex_unlock(&private->data_mutex);
}
ucontrol->value.integer.value[0] = private->vol[index];
return 0;
@ -1439,11 +1437,10 @@ static int scarlett2_dim_mute_ctl_get(struct snd_kcontrol *kctl,
struct usb_mixer_interface *mixer = elem->head.mixer;
struct scarlett2_data *private = mixer->private_data;
if (private->vol_updated) {
mutex_lock(&private->data_mutex);
if (private->vol_updated)
scarlett2_update_volumes(mixer);
mutex_unlock(&private->data_mutex);
}
ucontrol->value.enumerated.item[0] = private->dim_mute[elem->control];
return 0;