On Tue, Mar 18, 2025 at 05:51:40PM -0700, Wesley Cheng wrote: > In order to allow userspace/applications know about USB offloading status, > expose a sound kcontrol that fetches information about which sound card > and PCM index the USB device is mapped to for supporting offloading. In > the USB audio offloading framework, the ASoC BE DAI link is the entity > responsible for registering to the SOC USB layer. > > It is expected for the USB SND offloading driver to add the kcontrol to the > sound card associated with the USB audio device. An example output would > look like: > > tinymix -D 1 get 'USB Offload Playback Route PCM#0' > -1, -1 (range -1->255) > > This example signifies that there is no mapped ASoC path available for the > USB SND device. > > tinymix -D 1 get 'USB Offload Playback Route PCM#0' > 0, 0 (range -1->255) > > This example signifies that the offload path is available over ASoC sound > card index#0 and PCM device#0. > > The USB offload kcontrol will be added in addition to the existing > kcontrols identified by the USB SND mixer. The kcontrols used to modify > the USB audio device specific parameters are still valid and expected to be > used. These parameters are not mirrored to the ASoC subsystem. > > Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx> > --- > sound/usb/Kconfig | 10 ++ > sound/usb/qcom/Makefile | 4 + > sound/usb/qcom/mixer_usb_offload.c | 158 +++++++++++++++++++++++++++++ > sound/usb/qcom/mixer_usb_offload.h | 17 ++++ > sound/usb/qcom/qc_audio_offload.c | 2 + > 5 files changed, 191 insertions(+) > create mode 100644 sound/usb/qcom/mixer_usb_offload.c > create mode 100644 sound/usb/qcom/mixer_usb_offload.h > > diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig > index 6daa551738da..7d8833945711 100644 > --- a/sound/usb/Kconfig > +++ b/sound/usb/Kconfig > @@ -176,9 +176,19 @@ config SND_BCD2000 > To compile this driver as a module, choose M here: the module > will be called snd-bcd2000. > > +config SND_USB_QC_OFFLOAD_MIXER > + tristate "Qualcomm USB Audio Offload mixer control" This looks like a "bool" and not a "tristate", since the ifneq in the Makefile below ignores whether this is a "y" or "m". > + help > + Say Y to enable the Qualcomm USB audio offloading mixer controls. > + This exposes an USB offload capable kcontrol to signal to > + applications about which platform sound card can support USB > + audio offload. The returning values specify the mapped ASoC card > + and PCM device the USB audio device is associated to. > + > config SND_USB_AUDIO_QMI > tristate "Qualcomm Audio Offload driver" > depends on QCOM_QMI_HELPERS && SND_USB_AUDIO && USB_XHCI_SIDEBAND && SND_SOC_USB > + select SND_USB_OFFLOAD_MIXER And I think "SND_USB_OFFLOAD_MIXER" (without _QC suffix) doesn't exist anymore after v30? I see there was some discussion around that there. Is this supposed to be "select SND_USB_QC_OFFLOAD_MIXER"? If yes, isn't this option always selected if SND_USB_AUDIO_QMI is enabled? In that case you could just drop the config option... > help > Say Y here to enable the Qualcomm USB audio offloading feature. > > diff --git a/sound/usb/qcom/Makefile b/sound/usb/qcom/Makefile > index 1eb51160e2e5..1efe1b90be7a 100644 > --- a/sound/usb/qcom/Makefile > +++ b/sound/usb/qcom/Makefile > @@ -1,2 +1,6 @@ > snd-usb-audio-qmi-y := usb_audio_qmi_v01.o qc_audio_offload.o > obj-$(CONFIG_SND_USB_AUDIO_QMI) += snd-usb-audio-qmi.o > + > +ifneq ($(CONFIG_SND_USB_QC_OFFLOAD_MIXER),) > +snd-usb-audio-qmi-y += mixer_usb_offload.o > +endif Thanks, Stephan
