From: "Geoffrey D. Bennett" <g@b4.vu>
To: alsa-devel@alsa-project.org, Takashi Iwai <tiwai@suse.de>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>,
Vladimir Sadovnikov <sadko4u@gmail.com>
Subject: [PATCH 10/14] ALSA: usb-audio: scarlett2: Fix data_mutex lock
Date: Mon, 21 Jun 2021 02:16:43 +0930 [thread overview]
Message-ID: <20210620164643.GA9216@m.b4.vu> (raw)
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>
---
sound/usb/mixer_scarlett_gen2.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)
diff --git a/sound/usb/mixer_scarlett_gen2.c b/sound/usb/mixer_scarlett_gen2.c
index cb8483d3c58a..d6298ab1de56 100644
--- a/sound/usb/mixer_scarlett_gen2.c
+++ b/sound/usb/mixer_scarlett_gen2.c
@@ -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);
+ mutex_lock(&private->data_mutex);
+ if (private->vol_updated)
scarlett2_update_volumes(mixer);
- mutex_unlock(&private->data_mutex);
- }
+ 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);
+ mutex_lock(&private->data_mutex);
+ if (private->vol_updated)
scarlett2_update_volumes(mixer);
- mutex_unlock(&private->data_mutex);
- }
+ 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);
+ mutex_lock(&private->data_mutex);
+ if (private->vol_updated)
scarlett2_update_volumes(mixer);
- mutex_unlock(&private->data_mutex);
- }
+ mutex_unlock(&private->data_mutex);
ucontrol->value.enumerated.item[0] = private->dim_mute[elem->control];
return 0;
--
2.31.1
reply other threads:[~2021-06-20 16:51 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210620164643.GA9216@m.b4.vu \
--to=g@b4.vu \
--cc=alsa-devel@alsa-project.org \
--cc=htl10@users.sourceforge.net \
--cc=sadko4u@gmail.com \
--cc=tiwai@suse.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox