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List:       linux-kernel
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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