In case the USB backend device has not been initialized/probed, USB SND
device connections can still occur. When the USB backend is eventually
made available, previous USB SND device connections are not communicated to
the USB backend. Call snd_usb_rediscover_devices() to generate the connect
callbacks for all USB SND devices connected. This will allow for the USB
backend to be updated with the current set of devices available.
The chip array entries are all populated and removed while under the
register_mutex, so going over potential race conditions:
Thread#1:
q6usb_component_probe()
--> snd_soc_usb_add_port()
--> snd_usb_rediscover_devices()
--> mutex_lock(register_mutex)
Thread#2
--> usb_audio_disconnect()
--> mutex_lock(register_mutex)
So either thread#1 or thread#2 will complete first. If
Thread#1 completes before thread#2:
SOC USB will notify DPCM backend of the device connection. Shortly
after, once thread#2 runs, we will get a disconnect event for the
connected device.
Thread#2 completes before thread#1:
Then during snd_usb_rediscover_devices() it won't notify of any
connection for that particular chip index.
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409194804.3773260-19-quic_wcheng@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB SND needs to know how the USB offload path is being routed. This would
allow for applications to open the corresponding sound card and pcm device
when it wants to take the audio offload path. This callback should return
the mapped indexes based on the USB SND device information.
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409194804.3773260-18-quic_wcheng@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Expose API for creation of a jack control for notifying of available
devices that are plugged in/discovered, and that support offloading. This
allows for control names to be standardized across implementations of USB
audio offloading.
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409194804.3773260-17-quic_wcheng@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce a helper to check if a particular PCM format is supported by the
USB audio device connected. If the USB audio device does not have an
audio profile which can support the requested format, then notify the USB
backend.
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409194804.3773260-16-quic_wcheng@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some platforms may have support for offloading USB audio devices to a
dedicated audio DSP. Introduce a set of APIs that allow for management of
USB sound card and PCM devices enumerated by the USB SND class driver.
This allows for the ASoC components to be aware of what USB devices are
available for offloading.
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409194804.3773260-15-quic_wcheng@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
