Re: libata: CD and dvd devices not recognized

[Tejun Heo <htejun@gmail.com>]

Albert Lee wrote:
> Hi Yarema,
> 
> Thanks for the detailed log.
> It looks like the bad INQUIRY command
>   "CDB (4:0,1,0) 12 01 00 00 fe 00 00 00 00" (INQUIRY, length=254, EVPD=1)
> is coming from the user space, not the SCSI mid-layer.
> 
> I guess two problems together caused this bug:
> 1. Ubuntu Linux issues an incorrect INQUIRY command to the drive.
>    (Other distros seem to have the INQUIRY correct.)
> 2. The incorrect INQUIRY happens to cause the AOpen drive frozen.
>    (The HP drive is immune from the incorrect INQUIRY command.
>     "check condition" is returned for the bad INQUIRY.)
> 
> We have two possible solutions here:
> a. Patch Ubuntu, such that the incorrect INQUIRY is fixed.
> b. Patch kernel, such that the AOpen drives are blacklisted.
>    Each INQUIRY is inspected for the blacklisted drives.
>    If the INQUIRY looks wrong, the INQUIRY is rejected.
> 
> I guess a. is the preferred solution...

I second Albert's opinion.  Please report this to ubuntu people so that
the origin of the problem can be fixed.

Thanks a lot.  I admire your ability and patience in tracking these
difficult issues.  :-)

-- 
tejun