@@ -65,6 +65,7 @@ struct uac_rtd_params {
struct snd_kcontrol *snd_kctl_rate; /* read-only current rate */
int srate; /* selected samplerate */
+ int active; /* playback/capture running */
spinlock_t lock; /* lock for control transfers */
@@ -490,6 +491,21 @@ static inline void free_ep_fback(struct uac_rtd_params *prm, struct usb_ep *ep)
dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__);
}
+static void set_active(struct uac_rtd_params *prm, bool active)
+{
+ // notifying through the Rate ctrl
+ struct snd_kcontrol *kctl = prm->snd_kctl_rate;
+ unsigned long flags;
+
+ spin_lock_irqsave(&prm->lock, flags);
+ if (prm->active != active) {
+ prm->active = active;
+ snd_ctl_notify(prm->uac->card, SNDRV_CTL_EVENT_MASK_VALUE,
+ &kctl->id);
+ }
+ spin_unlock_irqrestore(&prm->lock, flags);
+}
+
int u_audio_set_capture_srate(struct g_audio *audio_dev, int srate)
{
struct uac_params *params = &audio_dev->params;
@@ -607,6 +623,8 @@ int u_audio_start_capture(struct g_audio *audio_dev)
dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
}
+ set_active(&uac->c_prm, true);
+
ep_fback = audio_dev->in_ep_fback;
if (!ep_fback)
return 0;
@@ -652,6 +670,7 @@ void u_audio_stop_capture(struct g_audio *audio_dev)
{
struct snd_uac_chip *uac = audio_dev->uac;
+ set_active(&uac->c_prm, false);
if (audio_dev->in_ep_fback)
free_ep_fback(&uac->c_prm, audio_dev->in_ep_fback);
free_ep(&uac->c_prm, audio_dev->out_ep);
@@ -723,6 +742,8 @@ int u_audio_start_playback(struct g_audio *audio_dev)
dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
}
+ set_active(&uac->p_prm, true);
+
return 0;
}
EXPORT_SYMBOL_GPL(u_audio_start_playback);
@@ -731,6 +752,7 @@ void u_audio_stop_playback(struct g_audio *audio_dev)
{
struct snd_uac_chip *uac = audio_dev->uac;
+ set_active(&uac->p_prm, false);
free_ep(&uac->p_prm, audio_dev->in_ep);
}
EXPORT_SYMBOL_GPL(u_audio_stop_playback);
@@ -1074,7 +1096,11 @@ static int u_audio_rate_get(struct snd_kcontrol *kcontrol,
unsigned long flags;
spin_lock_irqsave(&prm->lock, flags);
- ucontrol->value.integer.value[0] = prm->srate;
+ if (prm->active)
+ ucontrol->value.integer.value[0] = prm->srate;
+ else
+ /* not active: reporting zero rate */
+ ucontrol->value.integer.value[0] = 0;
spin_unlock_irqrestore(&prm->lock, flags);
return 0;
}
The Playback/Capture ctl currently reports rate value set by USB control selector UAC2_CS_CONTROL_SAM_FREQ (fixed for UAC1). When the stops playback/capture, the reported value does not change. The gadget side has no information whether the host has started/stopped capture/playback. This patch sets the value reported by the respective rate ctl to zero when the host side has stopped playback/capture. Also, it calls snd_ctl_notify when start/stop occurs, so that a subscribed client can act appropriately. Tests have confirmed that USB hosts change UAC2_CS_CONTROL_SAM_FREQ before switching altsetting to activate playback/capture, resulting in correct order (params->c/p_srate is set to requested rate before u_audio_start_capture/playback is called). The gadget rate notifications are used by user-space audio gadget controller gaudio_ctl https://github.com/pavhofman/gaudio_ctl. Signed-off-by: Pavel Hofman <pavel.hofman@ivitera.com> --- v3: * using prm->srate instead of params->c_srate/p_srate due to the added commit "[v3] usb: gadget: u_audio: Move dynamic srate from params to rtd" --- drivers/usb/gadget/function/u_audio.c | 28 ++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-)