Re: [linux-usb-devel] question on flushing buffers and spinning down disk

Am Montag 24 September 2007 schrieb Alan Stern:
> On Mon, 24 Sep 2007, Oliver Neukum wrote:
> 
> > > subsystem implements its own form of runtime PM support, then you'll be
> > > able to use it properly.  But until then, there isn't anything much you
> > > can do.
> > 
> > Well, we can't simply cut power. Buffers must be flushed and the disk
> > spun down. The suspend() method of the storage driver will have to become
> > complex.
> 
> That's right, if the device is a real disk.  If it's a flash memory
> device then of course these issues don't arise.  Unfortunately the

With respect to buffers how sure are you about that?

> driver isn't able to tell one from the other; the user will have to
> do that for us.

Code for what we need is in sd_suspend(). The only trouble is locking.
We need to make sure no commands that dirty buffers are issued after
flushing the buffers.

	Regards
		Oliver


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