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List:       linux-usb-devel
Subject:    Re: [linux-usb-devel] Problems with USB disk [solved]
From:       Mark Lord <lkml () rtr ! ca>
Date:       2007-09-13 15:21:07
Message-ID: 46E95563.5020704 () rtr ! ca
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Alan Stern wrote:
> On Thu, 13 Sep 2007, Mark Lord wrote:
..
>> What happens is, there's a nice little LED on the Cruzer stick,
>> that is "lit" when the stick itself is not in a "power suspend" state
>> (or whatever you USB folks call it).
> 
> We call it "suspended".  (Wasn't there an episode of Classic Trek where 
> Mr. Spock explained to somebody, "I call them `ears'."?)
> 
>> On 2.6.22, that little LED stays "on" normally, and flickers off/on
>> when data is being transfered.
>>
>> The new "USB autosuspend" logic in 2.6.23 now causes that little LED
>> to turn off after a few seconds of inactivity.
>>
>> Once that happens, the USB stick is not accessible until after a longish
>> timeout (~30s I think), followed by a USB reset.  Then it is usable again
>> until the next inactivity timeout and autosuspend (a few seconds).
> 
> So this _isn't_ the regression described above -- to wit, that the 
> drive gets spun down and then won't work without first being spun back 
> up.  You wrote:
> 
>>>> My Sandisk Cruzer Micro 1GB USB sticks suffer from this regression.
> 
> But it doesn't.  It suffers from a different regression.

Perhaps, but that doesn't necessarily follow from the above.
>From this observer's point of view (and being an expert on disk technologies),
the same "spin up" issue for rotating media could be the culprit here too.

A reset to a disk drive usually (not always) causes it to spin up.

Regardless, Greg has acknowledged the regression and is planning to revert things.

Cheers

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