Messages in this thread | | | Date | Mon, 5 Feb 2024 10:01:03 +0100 | Subject | Re: [PATCH v13 50/53] ALSA: usb-audio: Allow for rediscovery of connected USB SND devices | From | Amadeusz Sławiński <> |
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On 2/3/2024 3:36 AM, Wesley Cheng wrote: > In case of notifying SND platform drivers of connection events, some of > these use cases, such as offloading, require an ASoC USB backend device to > be initialized before the events can be handled. If the USB backend device > has not yet been probed, this leads to missing initial USB audio device > connection events. > > Expose an API that traverses the usb_chip array for connected devices, and > to call the respective connection callback registered to the SND platform > driver. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> > --- > sound/usb/card.c | 19 +++++++++++++++++++ > sound/usb/card.h | 2 ++ > sound/usb/qcom/qc_audio_offload.c | 2 ++ > 3 files changed, 23 insertions(+) > > diff --git a/sound/usb/card.c b/sound/usb/card.c > index 11b827b7a2a5..995b2df676ab 100644 > --- a/sound/usb/card.c > +++ b/sound/usb/card.c > @@ -202,6 +202,25 @@ struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx, > } > EXPORT_SYMBOL_GPL(snd_usb_find_suppported_substream); > > +/* > + * in case the platform driver was not ready at the time of USB SND > + * device connect, expose an API to discover all connected USB devices > + * so it can populate any dependent resources/structures. > + */ > +void snd_usb_rediscover_devices(void) > +{ > + int i; > + > + mutex_lock(®ister_mutex); > + for (i = 0; i < SNDRV_CARDS; i++) { > + if (usb_chip[i]) > + if (platform_ops && platform_ops->connect_cb) > + platform_ops->connect_cb(usb_chip[i]);
if inside if, it can just be && or maybe move callback check before mutex lock and just return early if it is not present?
> + } > + mutex_unlock(®ister_mutex); > +} > +EXPORT_SYMBOL_GPL(snd_usb_rediscover_devices); > + > /* > * disconnect streams > * called from usb_audio_disconnect() > diff --git a/sound/usb/card.h b/sound/usb/card.h > index 6d59995440c3..3a0d68f453a1 100644 > --- a/sound/usb/card.h > +++ b/sound/usb/card.h > @@ -222,11 +222,13 @@ int snd_usb_unregister_platform_ops(void); > #if IS_ENABLED(CONFIG_SND_USB_AUDIO) > struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx, > struct snd_pcm_hw_params *params, int direction); > +void snd_usb_rediscover_devices(void); > #else > static struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx, > struct snd_pcm_hw_params *params, int direction) > { > return NULL; > } > +static void snd_usb_rediscover_devices(void) { } > #endif /* IS_ENABLED(CONFIG_SND_USB_AUDIO) */ > #endif /* __USBAUDIO_CARD_H */ > diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c > index 08af82ec22ad..9b0f98600e58 100644 > --- a/sound/usb/qcom/qc_audio_offload.c > +++ b/sound/usb/qcom/qc_audio_offload.c > @@ -1867,6 +1867,8 @@ static int __init qc_usb_audio_offload_init(void) > if (ret < 0) > goto release_qmi; > > + snd_usb_rediscover_devices(); > + > return 0; > > release_qmi: >
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