Messages in this thread | | | Date | Mon, 5 Feb 2024 13:27:52 -0800 | Subject | Re: [PATCH v13 50/53] ALSA: usb-audio: Allow for rediscovery of connected USB SND devices | From | Wesley Cheng <> |
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Hi Amadeusz,
On 2/5/2024 1:01 AM, Amadeusz Sławiński wrote: > 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? >
Thanks for pointing that out. Makes sense, and will update it.
Thanks Wesley Cheng
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