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

Alan Stern
2007-09-13T14:19:52Z

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.

Alan Stern