Re: [PATCH v24 26/34] ALSA: usb-audio: qcom: Don't allow USB offload path if PCM device is in use

Pierre-Louis Bossart
2024-08-01T09:15:04Z

On 8/1/24 03:17, Wesley Cheng wrote:
> Add proper checks and updates to the USB substream once receiving a USB QMI
> stream enable request. If the substream is already in use from the non
> offload path, reject the stream enable request. In addition, update the
> USB substream opened parameter when enabling the offload path, so the
> non offload path can be blocked.

It's a bit weird that the mutual exclusion between the standard path and
the offloaded path is handled at the vendor level. I would think this
needs to be handled in the soc_usb framework, no?

> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
> ---
> sound/usb/qcom/qc_audio_offload.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c
> index 8b0913b7256b..3b46d05f1421 100644
> --- a/sound/usb/qcom/qc_audio_offload.c
> +++ b/sound/usb/qcom/qc_audio_offload.c
> @@ -1460,12 +1460,17 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle,
> goto response;
> }
>
> + mutex_lock(&chip->mutex);
> if (req_msg->enable) {
> - if (info_idx < 0 || chip->system_suspend) {
> + if (info_idx < 0 || chip->system_suspend || subs->opened) {
> ret = -EBUSY;
> + mutex_unlock(&chip->mutex);
> +
> goto response;
> }
> + subs->opened = 1;
> }
> + mutex_unlock(&chip->mutex);
>
> if (req_msg->service_interval_valid) {
> ret = get_data_interval_from_si(subs,
> @@ -1487,6 +1492,11 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle,
> if (!ret)
> ret = prepare_qmi_response(subs, req_msg, &resp,
> info_idx);
> + if (ret < 0) {
> + mutex_lock(&chip->mutex);
> + subs->opened = 0;
> + mutex_unlock(&chip->mutex);
> + }
> } else {
> info = &uadev[pcm_card_num].info[info_idx];
> if (info->data_ep_pipe) {
> @@ -1510,6 +1520,9 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle,
> }
>
> disable_audio_stream(subs);
> + mutex_lock(&chip->mutex);
> + subs->opened = 0;
> + mutex_unlock(&chip->mutex);
> }
>