Re: [Qemu-devel] [libvirt] [PATCH 3/5] qemu: add usb-bot support from disks points of view

[Daniel P. Berrange]

On Tue, Sep 03, 2013 at 09:51:52AM +0200, Gerd Hoffmann wrote:
> On Mo, 2013-09-02 at 13:57 +0100, Daniel P. Berrange wrote:
> > On Mon, Sep 02, 2013 at 05:38:42PM +0800, Guannan Ren wrote:
> > > usb-bot only supports 16 luns(0~15) and they must be contiguous,
> > > (using lun 0 and 2 without 1 doesn't work). In this case qemu
> > > doesn't throw an error, we can not find the lun 2 in guests. So
> > > Adding a checking function in libvirt to prevent from this case.
> > 
> > Hmm, this seems like a problematic restriction.
> 
> It's how the hardware works.
> 
> > How does this work if we start off a guest with 3 disks
> > attached to the usb-bot SCSI controller. Then hot-unplug
> > the 2nd disk.
> 
> You can't hotplug individual luns anyway.

How does hotplug/unplug work in the context of usb-bot ?

AFAIK we need to be able to run

  device_add usb_bot
  drive_add file...
  device_add scsi-hd

And the reverse, to unplug it, if we're to have feature parity with
usb-storage.


Daniel
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