Disable audio on the VM

[byrond]

Description

This adds flags to the call to modifyvm in the Vagrantfile to disable audio in the VM upon boot. If audio is enabled for a running VM, high CPU utilization will occur after waking the host from sleep.

(See https://forums.virtualbox.org/viewtopic.php?f=8&t=90027)

Testing instructions

• Halt all running VMs on the host, except one.
• Cause the host to sleep.
• Wait about a minute.
• Wake the host and notice high CPU utilization by the VBoxHeadless process in Activity Monitor.
• Add the changes in the PR to the Vagrant file of the running VM.
• vagrant halt && vagrant up ("reload" may not allow the audio to be disabled on the running VM; I haven't tested that)
• Cause the host to sleep.
• Wait about a minute.
• Wake the host and notice there is no longer high CPU utilization.

[becw]

This affects Virtualbox version 5.2.20 and up, right now.

[froboy]

I just tested this by manually copying the line into an existing VM and it solved my problem. I was having sporadic issues with by music playing on bluetooth headphones getting interrupted when I spun up a machine! Apart from... playing music on bluetooth headphones while running vagrant up, you can confirm this setting works by going into VirtualBox, checking the settings of your machine, and observing "Enable Audio" is off.

[geerlingguy]

Just found out about this PR through a comment on an HN thread for a blog post I wrote earlier today. I would like to also incorporate this change into Drupal VM — @byrond would you be willing to file a PR to add it to Drupal VM's Vagrantfile so I can credit you with the fix?

[geerlingguy]

Can confirm this fixes the weird audio issues I was experiencing.

[byrond]

@geerlingguy, sorry for the delay in responding. We are just coming back from our holiday break. I see this was already fixed in Drupal VM, but thanks for offering the opportunity for credit. No worries though! :)

[byrond]

This affects Virtualbox version 5.2.20 and up, right now.

This is still an issue without this patch on VirtualBox 5.2.30, only instead of high CPU after a host nap, a VM with audio enabled would be "aborted."