Re: [PATCH] scsi: Add QEMU CD-ROM to VPD Inquiry Blacklist

[Paolo Bonzini <pbonzini@redhat.com>]

On 06/06/2016 17:41, John Snow wrote:
> On 06/06/2016 11:05 AM, Paolo Bonzini wrote:
>> For ATAPI, you have to blacklist all versions up to 2.2 inclusive.
>>
>> This gives:
>>
>> - QEMU / QEMU CD-ROM / 0.8.    (this is IDE and SCSI)
>> - QEMU / QEMU CD-ROM / 0.9.    (this is IDE and SCSI)
>> - QEMU / QEMU CD-ROM / 0.10    (this is SCSI only)
>> - QEMU / QEMU CD-ROM / 0.11    (this is SCSI only)
>> - QEMU / QEMU DVD-ROM / 0.8.   (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 0.9.   (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 0.10   (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 0.11   (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 0.12   (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 0.13   (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 0.14   (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 0.15   (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 1.0    (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 1.1    (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 1.2    (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 1.3    (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 1.4    (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 1.5    (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 1.6    (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 1.7    (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 2.0    (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 2.1    (this is IDE only)
>> - QEMU / QEMU DVD-ROM / 2.2    (this is IDE only)
>>
> 
> If this bug is caused by a missing VPD response, Paolo's version history
> here is correct.... for upstream versions.
> 
> Various downstreams may have backported the VPD fix to older versions,
> we need to be careful not to block those, too ... so targeting the core
> behavior seems like the more strictly correct, easily maintainable solution.

I think this is not practical.  I'm okay with the big hammer if an
algorithmic fix is not feasible; but otherwise it does seem a better
idea than blacklisting based on inquiry data...

Thanks,

Paolo

> Why not just dynamically blacklist devices that fail to respond to VPD
> inquiries?