Re: [autosuspend] [ums] spin down the disk in the suspend() method of the storage driver

Alan Stern <[email protected]>
Newsgroups gmane.linux.usb.devel
Message-ID <[email protected]>
On Sun, 9 Sep 2007, Alexey Rempel wrote:

> i use "040d:6204 VIA Technologies, Inc."  ( USB->IDE Adapter) with 2,5
> hard drive what working perfectly except small issue with autosuspend.
> It can be suspended and resumed, so it seems like there is no problem
> power mangment in this adapter. But the way haw it will be suspended
> make me some worries: the adpater will be just powered off and hard
> drive make sound like air plain crash. Similar sound i heard on shutdown
>  of my laptop with broken libata or acpi, so far i know it is not really
> healthy for hard drive.
> 
> I think it should be done with some scenario like: 1. park heads, 2.
> spin down, 3. suspend the adapter.

You are correct, except for one thing: The change you propose (park
heads, spin down, and then suspend) involves the SCSI disk driver, not
the usb-storage driver.  In fact, the SCSI disk driver already contains 
code to do these things, although I believe you have to enable it by 
hand.

It's true that the autosuspend code in usb-storage does not spin down
the disk.  For this reason you should disable autosuspend in
usb-storage for your drive.  In future kernel releases the default will
be to disable autosuspend.  Then programs like HAL will enable
autosuspend for drives where it is known to be safe.

Alan Stern


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