Re: [Qemu-devel] [PATCH 0/3] add usb_detach and usb_attach (v3)

[Luiz Capitulino <lcapitulino@redhat.com>]

On Thu, 21 Oct 2010 15:27:23 +0200
Alon Levy <alevy@redhat.com> wrote:

> On Thu, Oct 21, 2010 at 08:13:19AM -0500, Anthony Liguori wrote:
> > On 10/21/2010 08:03 AM, Gerd Hoffmann wrote:
> > >On 10/21/10 08:36, Alon Levy wrote:
> > >>v2->v3 changes:
> > >>  * add configure parameter
> > >>  * fix docs
> > >>
> > >>v2 message:
> > >>This patchset uses id like device_del for attaching/detaching usb
> > >>devices. The first two patches ready the way:
> > >>  1. makes qdev_find_recursive non static and in qdev.h
> > >>  2. adds a usb_device_by_id which goes over the usb buses calling
> > >>   qdev_find_recursive
> > >>  3. adds the commands that use usb_device_by_id
> > >>
> > >>Alon Levy (3):
> > >>   qdev: make qdev_find_recursive public
> > >>   usb: add public usb_device_by_id
> > >>   monitor: add usb_attach and usb_detach (v2)
> > >>
> > >
> > >Acked-by: Gerd Hoffmann <kraxel@redhat.com>
> > 
> > Okay, I am still confused about the use-case for this and I don't
> > see any further explanation in the commit messages.  I've seen
> > "debugging" but can you be a bit more specific about which cases
> > it's needed for?
> 
> To elaborate a little more, when using a certificates based card
> there is no hardware event (i.e. removing/inserting the physical card)
> that causes a usb_detach/attach to the card (both in passthru and
> emulated), but otoh certificates is good for testing since it decouples
> it from NSS/tcp. So I needed some way to emulate an insert/remove, and
> I saw usb_del, which was pretty close, and voila. This is not the same
> as card remove/reinsert, but it is exactly what will happen to the
> guest when spicec connects/disconnects, since I detach devices on
> disconnect and attach on connect.

Looks reasonable to me, specially because this will be protected by
#ifdef DEBUG. I don't see a big deal in merging this.

Objections, Anthony?

> > This is just adding a HMP command.  Is that the right approach or
> > was that an unintentional consequence of rebasing post-HMP/QMP
> > split?

I don't think this should be available under QMP, it's more a debugging
command for USB developers.

> > 
> > Regards,
> > 
> > Anthony Liguori
> > 
> > >
> > >cheers,
> > >  Gerd
> > >
> > >
> > 
> > 
>