Re: [1/4] 2.6.23-rc6: known regressions

Greg KH
2007-09-13T14:41:39Z

On Thu, Sep 13, 2007 at 10:19:48AM -0400, Alan Stern wrote:
> On Thu, 13 Sep 2007, Greg KH wrote:
>
> > Ok, after conferring with Oliver this morning, I think the best solution
> > here is to both revert the usb-storage suspend patch as it has some
> > basic problems that can cause data loss, _and_ add the change to the
> > kernel that by default disables autosuspend on all USB devices except
> > hubs.
>
> Are you referring to the disk spin-down issue? As far as I know,
> that's the only troublesome aspect of usb-storage autosuspend (apart
> from the fact that so many devices don't seem to support it very well,
> if at all).
>
> Solving the spin-down problem will require coordination with the SCSI
> developers. Basically, the SCSI core has to notify the HBA driver
> whenever the bus has been idle sufficiently long and all its devices
> are ready to be suspended. In particular, all disk heads should be
> parked and drives spun down, if they need to be.

I am not sure. I will defer to Oliver for the knowledge of the details,
it was early in the morning and I can't remember them all exactly :)

(although it might be a few days for him to respond, he's here at a
conference without a laptop, so his lag time might be a bit longer than
normal...)

thanks,

greg k-h

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