Please support "-soundhw none"

[Josh Triplett]

qemu currently provides a default set of sound hardware. The -soundhw option can change that default set, such as by using "-soundhw pcspkr" to disable most of it, but no "-soundhw none" option exists to disable all of it. As far as I can tell, disabling the default sound hardware requires specifying -nodefaults and then manually specifying all the desired hardware, leaving out sound hardware.

Please consider adding support for "-soundhw none", to disable all the default sound hardware.

[Paolo Bonzini (bonzini)]

Actually, QEMU doesn't provide a default set of sound hardware.

The pcspk device provides port 0x61 and like most other legacy ISA devices is not removed by -nodefaults (i8254 PIT, i8257 DMA, i8259 PIC; only the serial port can be removed).

However, unless you configure it specifically with "-soundhw pcspk", the pcspk device does not emit any audio and is little more than an bolted-on piece of the PIT device model. You can check it yourself by placing a breakpoint on pcspk_audio_init and pcspk_realizefn. With -nodefaults, the latter does run, just like with no command line option, but pcspk_audio_init is not called. With -soundhw pcspk, both are called.

[VinceLe (legoll)]

It looks like qemu without any specific -soundhw CLI option uses pulseaudio.
So I still think a -soundhw none would be nice to have.

[Daniel Berrange (berrange)]

Pulseaudio is a sound *backend*. This is independent of the choice of guest hardware frontend.

You can disable pulseaudio using an env variable QEMU_AUDIO_DRV=none