Hi, I'm experiencing several issues related to sound using usb-audio when running qemu-system-ppc in Linux and Windows. Guests tried are Mac OS 9.2 and Mac OS X 10.0, 10.1, 10.2 and 10.3. (10.4 and 10.5 never have the usb-audio device available for audio playback, even though the device is recognised in the OS X system profiler.) It is hit and miss whether the audio device is actually available upon boot in 9.2 and the other versions of OS X. Qemu version tried is current master (Oct 25th), Windows version is cross-compiled from Fedora 30. I do not think there is any regression going on here, these are just issues that have been present for a long time. General issue: when audio is played, it almost always sounds crackling. For reasons of size, I uploaded 3 logs obtained in Linux running Mac OS X 10.3 with -trace "usb*" to: https://surfdrive.surf.nl/files/index.php/s/YfVVxEE3cHXkFPf/download 1. Log_no_audio_available.txt 2. Log_audio_available_2_sounds_played.txt 3. Log_audio_available_multi_sounds_played_untill_hangup.txt General issue in Linux (fedora 30)(which seems related to bug https://bugs.launchpad.net/qemu/+bug/1623998): [hsp@fedora30 qemu-master]$ ./startqemu.sh pulseaudio: set_sink_input_volume() failed pulseaudio: Reason: Invalid argument pulseaudio: set_sink_input_mute() failed pulseaudio: Reason: Invalid argument General issue in Windows 10: I always get to a point where this is logged: dsound: Could not lock playback buffer dsound: Reason: An invalid parameter was passed to the returning function dsound: Failed to lock buffer Linux specific. Qemu invocation for Mac OS 9.2: ./qemu-system-ppc -L pc-bios -boot c -M mac99 -m 512 \ -drive file=~/Mac-disks/9.2.img,format=raw,media=disk \ -serial stdio -sdl -device usb-audio -trace "*aud*" This immediately starts logging: 7380@1571817102.833929:audio_timer_start interval 10 ms 7380@1571817125.207880:audio_timer_delayed interval 16 ms 7380@1571817129.046816:audio_timer_delayed interval 16 ms Any movement of a window on the Linux desktop results in additional audio_timer_delayed logging. The audio_timer_delayed never stops. In Mac OS 9.2, the desktop icons disappear after some seconds of running, so the system cannot be stopped normally. Running the GTK GUI, only this is logged (no additional logging when moving windows). 14130@1571988483.402017:audio_timer_start interval 10 ms But the icons on the desktop also disappear. When running Mac OS X 10.X and clicking some system sounds, I see: 12134@1571818709.446031:audio_timer_start interval 10 ms 12134@1571818710.195023:audio_timer_stop 12134@1571818714.951030:audio_timer_start interval 10 ms 12134@1571818715.432959:audio_timer_stop 12134@1571818717.171045:audio_timer_start interval 10 ms 12134@1571818717.714323:audio_timer_stop 12134@1571818718.072381:audio_timer_start interval 10 ms 12134@1571818719.114544:audio_timer_stop After randomly clicking some system sounds more, the timer starts delaying and no longer stops: 12134@1571818893.564793:audio_timer_stop 12134@1571818895.698040:audio_timer_start interval 10 ms 12134@1571818899.961673:audio_timer_delayed interval 15 ms 12134@1571818900.472716:audio_timer_delayed interval 15 ms 12134@1571818902.759007:audio_timer_delayed interval 15 ms 12134@1571818905.803400:audio_timer_delayed interval 15 ms But the systems stays responsive, so can be shut down. Windows specific. Invocation: qemu-system-ppc.exe -L pc-bios -boot c -M mac99 -m 512 ^ -drive file=C:\Mac-disks\9.2.img,format=raw,media=disk ^ -serial stdio -sdl -device usb-audio -trace "*aud*" This immediately starts logging the audio_timer_start interval and never stops. Icons disappear from the desktop after some seconds. When running Mac OS X 10.X, playing just two system sounds results in: 2380@1571822566.040790:audio_timer_start interval 10 ms 2380@1571822566.108279:audio_timer_delayed interval 22 ms 2380@1571822566.128820:audio_timer_delayed interval 20 ms 2380@1571822566.150509:audio_timer_delayed interval 22 ms 2380@1571822566.172112:audio_timer_delayed interval 21 ms ...... 2380@1571822566.561345:audio_timer_delayed interval 21 ms 2380@1571822566.583846:audio_timer_delayed interval 22 ms 2380@1571822566.600482:audio_timer_delayed interval 15 ms 2380@1571822566.610111:audio_timer_stop 2380@1571822572.226433:audio_timer_start interval 10 ms 2380@1571822572.250866:audio_timer_delayed interval 24 ms 2380@1571822572.269819:audio_timer_delayed interval 18 ms ...... 2380@1571822572.452403:audio_timer_delayed interval 20 ms 2380@1571822572.474190:audio_timer_delayed interval 21 ms 2380@1571822572.509474:audio_timer_delayed interval 35 ms dsound: Could not lock playback buffer dsound: Reason: An invalid parameter was passed to the returning function dsound: Failed to lock buffer 2380@1571822572.560505:audio_timer_delayed interval 51 ms 2380@1571822572.581102:audio_timer_delayed interval 19 ms 2380@1571822572.600912:audio_timer_delayed interval 19 ms There is no saying when audio_timer_delayed will start displaying constantly. Only when one set of: 2260@1571823472.652244:audio_timer_start interval 10 ms 2260@1571823473.198349:audio_timer_stop Is following directly after each other, sound is played somewhat correctly. After randomly clicking several system sounds, the audio_timer_delayed message never stops. Thanks for looking into this. If there is any additional information needed, or disk images of Mac OS 9.2 or OS X 10.3 are required, please let me know. Best, Howard ps: thanks to Zoltan for pointing out I sent the original message into an earlier thread ;-)