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Title: SPICE audio backend never registers SPICE_INTERFACE_RECORD for sb16 device — microphone input silently non-functional #7773

Description

@Monty

Describe the issue
Microphone recording never works in the guest, regardless of guest-side configuration (confirmed recording device correctly selected in guest Multimedia Properties) and regardless of UTM's Sound Backend setting. Playback works correctly.

Debug log shows QEMU's SPICE server registers a playback interface immediately (spice_server_add_interface: SPICE_INTERFACE_PLAYBACK) and the client constructs a corresponding playback-N:0 channel. No SPICE_INTERFACE_RECORD interface is ever added by the server, and no record-N:0 channel is ever constructed by the client — not at VM start, and not when the guest actively attempts to record (tested via Windows Sound Recorder). macOS's own microphone permission system (TCC) is never invoked at all — confirmed via Console.app showing no kTCCServiceMicrophone entries and no orange mic-in-use indicator in the menu bar during a recording attempt — indicating the failure occurs entirely within QEMU's audio backend, before any host-level capture is attempted.

Configuration

  • UTM Version: 4.7.5
  • macOS Version: tahoe
  • Mac Chip (Intel, M1, ...): M4

Debug log
debug-02.log.zip

Steps to reproduce
Create/run a Windows 98 VM with sb16 sound device and -audiodev spice
Confirm playback works (it does)
Attempt to record via Windows Sound Recorder with correct recording device selected
Enable UTM Debug Log; observe SPICE_INTERFACE_PLAYBACK is added but SPICE_INTERFACE_RECORD never is

Expected behavior
A record interface/channel should be established when the guest opens the SB16 device for input, matching the existing playback behavior.

Note
The VM was originally set up from a preconfigured Windows 98 image (https://github.com/ducbao414/utm-windows-98), but the relevant QEMU device configuration (sb16 sound device on -audiodev spice) is identical to what UTM's own New VM wizard generates for a Windows 95/98 target — I confirmed this by creating a fresh VM through the wizard and comparing the generated arguments.

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