On Wed, May 8, 2013 at 10:12 PM, Robert <[email protected]> wrote:
> On Mit, 2013-05-08 at 12:25 +0000, Ming Lei wrote:
>> From the usbmon in correct case, there is no any ATA commands
>> at all. I am not sure where these commands are from(user space
>> or kernel?) in the failure case.
>
> I suspect it's strictly kernel - I didn't even mount the drive. Mounting
> is definitely possible (the drive works fine), but I wanted to show the
> minimal difference.

No, in fact, the scsi layer(sd, kernel) has already read the 4 sectors from
the device successfully, then one inquiry command and some RAW ATA
commands are sent to device, and the disk starts to behave badly. It is
very possible that these commands are sent from userspace when the scsi
disk device shows up and udevd got the notification. And these commands
aren't sent to the device absolutely on precise.

Looks some utilities(smartctl, hdparm) may do that.

>
>> Could you install the upstream 3.9.0 kernel images on 12.04 to
>> see if the HDD can work well?
>
> Sorry, not possible (production machine). I also don't see what would it
> bring, as the machine with 13.04 that shows the errors was working fine
> with 12.04.

Sorry to see that, but you already installed 3.9.0 upstream kernel on
raring(13.04),
right? I am wondering there is any difference to install 3.9.0 kernel on 12.04.

>
>> Another difference is that length of the 2nd INQUIRY command becomes
>> 12 instead of 6, which need to check further.
>
> Please do and let me know.

As I commented above, the 2nd inquiry command might be sent from
user space application.

Thanks,

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https://bugs.launchpad.net/bugs/1176355

Title:
  Can't access USB external disk

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