Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f9e5d013 authored by Geoffrey D. Bennett's avatar Geoffrey D. Bennett Committed by Greg Kroah-Hartman
Browse files

ALSA: usb-audio: scarlett2: Fix data_mutex lock 



[ Upstream commit 9b5ddea9ce5a68d7d2bedcb69901ac2a86c96c7b ]

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: default avatarGeoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/20210620164643.GA9216@m.b4.vu


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 33251aa2

sound/usb/mixer_scarlett_gen2.c

+9 −12
Original line number Diff line number Diff line
@@ -1033,11 +1033,10 @@ static int scarlett2_master_volume_ctl_get(struct snd_kcontrol *kctl, 
	struct usb_mixer_interface *mixer = elem->head.mixer;

	struct scarlett2_mixer_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;
@@ -1051,11 +1050,10 @@ static int scarlett2_volume_ctl_get(struct snd_kcontrol *kctl, 
	struct scarlett2_mixer_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;
@@ -1319,11 +1317,10 @@ static int scarlett2_button_ctl_get(struct snd_kcontrol *kctl, 
	struct usb_mixer_interface *mixer = elem->head.mixer;

	struct scarlett2_mixer_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->buttons[elem->control];

	return 0;