prepare_qmi_response(9)

💖 NAME 💖

Okay bestie, this is prepare_qmi_response(9) from the Kernel API Manual — and it is literally here to prepare stream enable response. That's the whole errand. 🎀

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✨ SYNOPSIS ✨

       int prepare_qmi_response (struct snd_usb_substream *subs , struct
       qmi_uaudio_stream_req_msg_v01 *req_msg , struct
       qmi_uaudio_stream_resp_msg_v01 *resp , int info_idx );

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🎀 ARGUMENTS 🎀

• subs — the usb substream, type struct snd_usb_substream *. That's the audio-pipe bestie in question. 🫶
• req_msg — the QMI request message, type struct qmi_uaudio_stream_req_msg_v01 *. The ask. The incoming vibe. 💌
• resp — the QMI response buffer, type struct qmi_uaudio_stream_resp_msg_v01 *. The lil' response glow-up goes here. ✨
• info_idx — the usb interface array index, type int. It's giving "which interface, bestie?" 🔎

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🦋 DESCRIPTION 🦋

So here's the tea: prepare_qmi_response() prepares the QMI response for a USB QMI stream enable request. It parses out the parameters inside the stream enable request, all so it can match the requested audio profile to the ones exposed by the USB device connected. Lowkey iconic matching behavior. 💅

On top of that, it fetches the XHCI transfer resources needed for the handoff to happen. That includes transfer ring and buffer addresses and secondary event ring address. These parameters get communicated as part of the USB QMI stream enable response. No cap, it's all about getting the response fully dressed for the handoff. 🌈

Bestie, this is a kernel-internal helper — it's not out here doing vibes-only work. It's parsing request parameters, matching audio profiles, and pulling XHCI transfer resources so the response carries what the handoff needs. Periodt. 💜

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🌸 SEE ALSO 🌸

Go peek at the kernel file ./sound/usb/qcom/qc_audio_offload.c, plus these icon functions:

• uaudio_iommu_unmap(9)
• uaudio_iommu_map_pa(9)
• uaudio_dev_intf_cleanup(9)
• uaudio_event_ring_cleanup_free(9)
• disable_audio_stream(9)
• uaudio_sideband_notifier(9)
• qmi_bye_cb(9)
• qmi_svc_disconnect_cb(9)
• enable_audio_stream(9)
• uaudio_transfer_buffer_setup(9)
• uaudio_endpoint_setup(9)
• uaudio_event_ring_setup(9)
• uaudio_populate_uac_desc(9)
• handle_uaudio_stream_req(9)
• qc_usb_audio_offload_init_qmi_dev(9)
• qc_usb_audio_offload_probe(9)
• qc_usb_audio_cleanup_qmi_dev(9)
• qc_usb_audio_offload_disconnect(9)
• qc_usb_audio_offload_suspend(9)

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Okay bye bestie — this page comes from ./sound/usb/qcom, dated October 2026, and it's literally called prepare_qmi_response(9). Mwah 💋✨