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Re: [Qemu-devel] [PATCH 0/3] add usb_detach and usb_attach (v3)
From: |
Luiz Capitulino |
Subject: |
Re: [Qemu-devel] [PATCH 0/3] add usb_detach and usb_attach (v3) |
Date: |
Fri, 22 Oct 2010 11:17:44 -0200 |
On Fri, 22 Oct 2010 07:55:02 -0500
Anthony Liguori <address@hidden> wrote:
> On 10/22/2010 07:48 AM, Luiz Capitulino wrote:
> > On Thu, 21 Oct 2010 15:27:23 +0200
> > Alon Levy<address@hidden> 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<address@hidden>
> >>>>
> >>> 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.
> >
>
> I'd just like to see better documentation. A command isn't useful for
> debugging if noone knows how to use it.
>
> Guarding with an #ifdef isn't necessary. It should be unconditionally
> enabled otherwise it will bit rot.
You and Gerd asked about the purpose of this command, turns out that it's
only useful for developing new USB devices for QEMU, so I thought it would
be better to restrict it, so that people don't start using this the
wrong way or worse, we can't drop/break it because some tool is now using it.
Anyway, maybe a good doc will do, this was just a small suggestion.
>
> > Objections, Anthony?
> >
>
> Not with better docs.
>
> Regards,
>
> Anthony Liguori
>
> >>> 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
> >>>>
> >>>>
> >>>>
> >>>
> >>>
> >>
> >
>
- [Qemu-devel] [PATCH 1/3] qdev: make qdev_find_recursive public, (continued)
- [Qemu-devel] [PATCH 1/3] qdev: make qdev_find_recursive public, Alon Levy, 2010/10/21
- [Qemu-devel] [PATCH 2/3] usb: add public usb_device_by_id, Alon Levy, 2010/10/21
- [Qemu-devel] [PATCH 3/3] monitor: add usb_attach and usb_detach (v2), Alon Levy, 2010/10/21
- Re: [Qemu-devel] [PATCH 0/3] add usb_detach and usb_attach (v3), Gerd Hoffmann, 2010/10/21
- Re: [Qemu-devel] [PATCH 0/3] add usb_detach and usb_attach (v3), Anthony Liguori, 2010/10/21
- Re: [Qemu-devel] [PATCH 0/3] add usb_detach and usb_attach (v3), Alon Levy, 2010/10/21
- Re: [Qemu-devel] [PATCH 0/3] add usb_detach and usb_attach (v3), Luiz Capitulino, 2010/10/22
- Re: [Qemu-devel] [PATCH 0/3] add usb_detach and usb_attach (v3), Anthony Liguori, 2010/10/22
- Re: [Qemu-devel] [PATCH 0/3] add usb_detach and usb_attach (v3),
Luiz Capitulino <=
- Re: [Qemu-devel] [PATCH 0/3] add usb_detach and usb_attach (v3), Anthony Liguori, 2010/10/22
- Re: [Qemu-devel] [PATCH 0/3] add usb_detach and usb_attach (v3), Luiz Capitulino, 2010/10/22
- Re: [Qemu-devel] [PATCH 0/3] add usb_detach and usb_attach (v3), Alon Levy, 2010/10/25