On 03/04/10 04:58 PM, Alan Stern wrote:
> On Sat, 3 Apr 2010, Jonas Schwertfeger wrote:
>
>> On 04/03/2010 06:42 PM, Alan Stern wrote:
>>> Can you acquire a usbmon trace showing what happens when you run this?
>>> Instructions are in the kernel source file
>>> Documentation/usb/usbmon.txt.
>>
>> Here you go:
>>
>> ffff8802123996c0 4253708718 S Bo:10:002:2 -115 31 = 55534243 9c000000
>> 00020000 80001085 082e0000 00010000 00000000 40ec00
>
> That's the first command.
>
>> ffff8802123996c0 4253708828 C Bo:10:002:2 0 31>
>> ffff8801f36c6a80 4253708841 S Bi:10:002:1 -115 512<
>> ffff8801f36c6a80 4253714580 C Bi:10:002:1 0 512 Z
>> ffff8802123996c0 4253714599 S Bi:10:002:1 -115 13<
>> ffff8802123996c0 4253714639 C Bi:10:002:1 0 13 = 55534253 9c000000
>> 00000000 00
>
> And it apparently succeeded.  It's not clear why hdparm reports "bad
> response".  Maybe it just doesn't like the data returned by the device.
>
>> ffff8802123996c0 4253714778 S Bo:10:002:2 -115 31 = 55534243 9d000000
>> 00020000 80001085 082e0000 00010000 00000000 40a100
>
> That's the second command, now presumably specifying a sector count of
> 1.
>
>> ffff8802123996c0 4253714813 C Bo:10:002:2 0 31>
>> ffff8801f36c6a80 4253714823 S Bi:10:002:1 -115 512<
>> ffff8801f36c6a80 4253715081 C Bi:10:002:1 -32 0
>> ffff8802123996c0 4253715119 S Co:10:002:0 s 02 01 0000 0081 0000 0
>> ffff8802123996c0 4253715383 C Co:10:002:0 0 0
>> ffff8802123996c0 4253715406 S Bi:10:002:1 -115 13<
>> ffff8802123996c0 4253715648 C Bi:10:002:1 0 13 = 55534253 9d000000
>> 00020000 01
>
> It failed.  But unlike your earlier experience, it didn't get a
> transport error.  A failure is more benign than an error; in particular
> it doesn't call for a reset.
>
>> ffff8802123996c0 4253715661 S Bo:10:002:2 -115 31 = 55534243 9e000000
>> 60000000 80000603 00000060 00000000 00000000 000000
>> ffff8802123996c0 4253715707 C Bo:10:002:2 0 31>
>> ffff8801f36c6a80 4253715723 S Bi:10:002:1 -115 96<
>> ffff8801f36c6a80 4253715763 C Bi:10:002:1 0 96 Z
>> ffff8802123996c0 4253715779 S Bi:10:002:1 -115 13<
>> ffff8802123996c0 4253715819 C Bi:10:002:1 0 13 = 55534253 9e000000
>> 00000000 00
>
> Here usb-storage asked the reason for the failure.  Unfortunately we
> can't see the response.  Did you run this on a computer with more than
> 1 GB of memory?  If you did, can you boot with "mem�0M" and try
> again?
>
>> ffff8802123996c0 4253717330 S Bo:10:002:2 -115 31 = 55534243 9f000000
>> 00100000 80000a28 00000000 00000008 00000000 000000
>> ffff8802123996c0 4253717373 C Bo:10:002:2 0 31>
>> ffff880211ace240 4253717386 S Bi:10:002:1 -115 4096<
>> ffff880211ace240 4253731794 C Bi:10:002:1 0 4096 Z
>> ffff8802123996c0 4253731815 S Bi:10:002:1 -115 13<
>> ffff8802123996c0 4253731854 C Bi:10:002:1 0 13 = 55534253 9f000000
>> 00000000 00
>
> This is a standard READ(10) command, asking for the first 8 sectors on
> the disk.  It succeeded.
>
> Alan Stern

I'll have a look at this stuff next week, after the Easter holiday.

Cheers
-- 
Mark Lord
Real-Time Remedies Inc.
mlord@pobox.com