[vbox-dev] Question regarding USB support under VirtualBOX

Klaus Espenlaub klaus.espenlaub at oracle.com
Wed Jan 26 08:46:41 PST 2011

On 23.01.2011 17:36, Hans Petter Selasky wrote:
> Hi,
> During usage of VirtualBOX under FreeBSD 8.2, I've noticed that the VM
> sometimes crashes if the USB string descriptors or other descriptors cannot be
> read or the device itself cannot be created, because the device is not
> responding.
>  From what I can understand VirtualBox USB enumeration has two stages:
> 1) Identifying devices
> 2) Probing devices
> There is no guarantee that identified devices won't disappear until they are
> probed. Should the FreeBSD USB layer in this case return fake status values,
> to avoid VirtualBOX from asserting.

This is extremely vague, as it we have many thousand assertions spread 
all over the VirtualBox code.

Generally it would be helpful to have a VBox.log with the assertion.

> 3) Reading any USB descriptor could theoretically fail at any time. The USB
> 1/2 specification specifies the STALL message, and there can be bus errors
> aswell. Who is responsible for hiding these failures, so that the VirtualBOX
> machine does not assert()?

Again - what assertion?


> --HPS
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