Re: [Qemu-devel] [PATCH 2/4] usb: add attached property

[Markus Armbruster]

Suggest to say

    usb: Add QOM property "attached"

The quotes make more obvious that "attached" is a property name, not an
adjective tacked to property.

Gerd Hoffmann <address@hidden> writes:

> USB devices in attached state are visible to the guest.

If I read the code correctly:

* ->attached is true between usb_device_attach() and usb_device_detach()

* Attach and detach is automatic on realize and unrealize, but a device
  can choose to suppress attach on realize, by unsetting ->auto_attach,
  and manage attach/detach itself.

* A detached device is wired up normally in QOM, but the USB core treats
  it as not plugged into its USB port.

Correct?

>                                                          This patch adds
> a QOM property for this.  Write access is opt-in per device.  Some
> devices manage attached state automatically (usb-host, usb-serial), so

Full list of devices unsetting ->auto_attach: dev-serial.c dev-storage.c
host-libusb.c redirect.c.

dev-storage.c does it only for encrypted media without a key, but that
should go away with Dan's "Support LUKS encryption in block devices", so
I guess neglecting to mention it here is okay.

Suggest to add usb-redir to your list.

> we can't enable write access universally but have to do it on a case by
> case base.

Suggest to add: So far, no device opts in.

>
> Signed-off-by: Gerd Hoffmann <address@hidden>

Patch looks good.