The Playback/Capture ctl currently reports rate value set by USB control selector UAC2_CS_CONTROL_SAM_FREQ (fixed for UAC1). When the host has stopped 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@xxxxxxxxxxx> --- drivers/usb/gadget/function/u_audio.c | 46 ++++++++++++--------------- 1 file changed, 21 insertions(+), 25 deletions(-) diff --git a/drivers/usb/gadget/function/u_audio.c b/drivers/usb/gadget/function/u_audio.c index e737a104156d..a6293415c071 100644 --- a/drivers/usb/gadget/function/u_audio.c +++ b/drivers/usb/gadget/function/u_audio.c @@ -64,6 +64,7 @@ struct uac_rtd_params { int mute; struct snd_kcontrol *snd_kctl_rate; /* read-only current rate */ + int rep_srate; /* srate reported by snd_kctl_rate */ spinlock_t lock; /* lock for control transfers */ @@ -496,8 +497,6 @@ static inline void free_ep_fback(struct uac_rtd_params *prm, struct usb_ep *ep) int u_audio_set_capture_srate(struct g_audio *audio_dev, int srate) { struct uac_params *params = &audio_dev->params; - struct snd_uac_chip *uac = audio_dev->uac; - struct uac_rtd_params *prm = &uac->c_prm; int i; dev_dbg(&audio_dev->gadget->dev, "%s: srate %d\n", __func__, srate); @@ -516,8 +515,6 @@ EXPORT_SYMBOL_GPL(u_audio_set_capture_srate); int u_audio_set_playback_srate(struct g_audio *audio_dev, int srate) { - struct snd_uac_chip *uac = audio_dev->uac; - struct uac_rtd_params *prm = &uac->p_prm; struct uac_params *params = &audio_dev->params; int i; @@ -535,6 +532,18 @@ int u_audio_set_playback_srate(struct g_audio *audio_dev, int srate) } EXPORT_SYMBOL_GPL(u_audio_set_playback_srate); +static void set_reported_srate(struct uac_rtd_params *prm, int srate) +{ + struct snd_kcontrol *kctl = prm->snd_kctl_rate; + + if (prm->rep_srate != srate) { + prm->rep_srate = srate; + snd_ctl_notify(prm->uac->card, SNDRV_CTL_EVENT_MASK_VALUE, + &kctl->id); + pr_debug("Setting '%s' to %d", kctl->id.name, srate); + } +} + int u_audio_start_capture(struct g_audio *audio_dev) { struct snd_uac_chip *uac = audio_dev->uac; @@ -574,6 +583,8 @@ int u_audio_start_capture(struct g_audio *audio_dev) dev_err(dev, "%s:%d Error!\n", __func__, __LINE__); } + set_reported_srate(&uac->c_prm, params->c_srate); + ep_fback = audio_dev->in_ep_fback; if (!ep_fback) return 0; @@ -619,6 +630,7 @@ void u_audio_stop_capture(struct g_audio *audio_dev) { struct snd_uac_chip *uac = audio_dev->uac; + set_reported_srate(&uac->c_prm, 0); 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); @@ -691,6 +703,8 @@ int u_audio_start_playback(struct g_audio *audio_dev) dev_err(dev, "%s:%d Error!\n", __func__, __LINE__); } + set_reported_srate(&uac->p_prm, params->p_srate); + return 0; } EXPORT_SYMBOL_GPL(u_audio_start_playback); @@ -699,6 +713,7 @@ void u_audio_stop_playback(struct g_audio *audio_dev) { struct snd_uac_chip *uac = audio_dev->uac; + set_reported_srate(&uac->p_prm, 0); free_ep(&uac->p_prm, audio_dev->in_ep); } EXPORT_SYMBOL_GPL(u_audio_stop_playback); @@ -1001,19 +1016,6 @@ static int get_max_srate(const int *srates) return max_srate; } -static int get_min_srate(const int *srates) -{ - int i, min_srate = INT_MAX; - - for (i = 0; i < UAC_MAX_RATES; i++) { - if (srates[i] == 0) - break; - if (srates[i] < min_srate) - min_srate = srates[i]; - } - return min_srate; -} - static int uac_pcm_rate_info(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_info *uinfo) { @@ -1030,7 +1032,7 @@ static int uac_pcm_rate_info(struct snd_kcontrol *kcontrol, srates = params->c_srates; else srates = params->p_srates; - uinfo->value.integer.min = get_min_srate(srates); + uinfo->value.integer.min = 0; uinfo->value.integer.max = get_max_srate(srates); return 0; } @@ -1039,14 +1041,8 @@ static int uac_pcm_rate_get(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol) { struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol); - struct snd_uac_chip *uac = prm->uac; - struct g_audio *audio_dev = uac->audio_dev; - struct uac_params *params = &audio_dev->params; - if (prm == &uac->c_prm) - ucontrol->value.integer.value[0] = params->c_srate; - else - ucontrol->value.integer.value[0] = params->p_srate; + ucontrol->value.integer.value[0] = prm->rep_srate; return 0; } -- 2.25.1
