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From: Markus Armbruster <armbru@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v2 1/3] scsi-disk: Allow overriding SCSI
	INQUIRY removable bit
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Date: Fri, 21 Jan 2011 18:38:47 +0100
In-Reply-To: <4D396987.7070903@redhat.com> (Kevin Wolf's message of "Fri, 21
	Jan 2011 12:09:59 +0100")
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To: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>, Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>, qemu-devel@nongnu.org, "Justin M. Forbes" <jforbes@redhat.com>, Christoph Hellwig <hch@lst.de>

Kevin Wolf <kwolf@redhat.com> writes:

> Am 21.01.2011 11:45, schrieb Stefan Hajnoczi:
>> On Tue, Jan 18, 2011 at 12:06 PM, Stefan Hajnoczi <stefanha@gmail.com> wrote:
>>> On Tue, Jan 18, 2011 at 11:39 AM, Kevin Wolf <kwolf@redhat.com> wrote:
>>>> Am 18.01.2011 11:10, schrieb Stefan Hajnoczi:
>>>>> Provide the "removable" qdev property bit to override the SCSI INQUIRY
>>>>> removable (RMB) bit for non-CDROM devices.  This will be used by USB
>>>>> Mass Storage Devices, which sometimes have this guest-visible bit set
>>>>> and sometimes do not.  They therefore requires a means for user
>>>>> configuration.
>>>>>
>>>>> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
>>>>
>>>> Should we print an error message when the user tries to make a CD-ROM
>>>> non-removable instead of silently ignoring the option?
>>>
>>> Good point.  I will add a check in scsi_disk_initfn() for v3.
>> 
>> Actually this case is hard to check against.  The removable property
>> is a boolean that defaults to false.  We can't detect the difference
>> between default, cleared, or set.
>
> Hm, I see... Maybe we should make scsi-disk and scsi-cdrom different
> devices in the long run,

Yes.  Need to dig out and rebase my patches for it.

>                          then scsi-cdrom could default to true (or
> rather not have the property at all).
>
>> I'm sending out a new version of the patch series that updates
>> docs/qdev-device-use.txt to describe how the removable property works.
>
> Okay, let's just document how it works.
>
> Kevin