Simon Shapiro wrote:
> On 10-May-00 Mike Smith wrote:
> >> Sorry to bother y'll, but;
> >> 
> >> Has anyone ever used that?  I see no trace of any kernel
> >> code calling it, and the at_shutdown code appears to be
> >> gone.
> > 
> > It's still used in the shutdown code; it was meant to be available for 
> > general use elsewhere, but I haven't seen anyone playing with it, so 
> > maybe the design tradeoffs were bad choices.
> I dunno.  It seems to do anything I need;  Call me with an argument.
> I do not even need the priority.

Well, you need to be called at "shutdown_post_sync" - anything before
that is too soon as the kernel is still potentially pushing data out to
the controller.  This also happens to be where the module and bus shutdown
events are called too.

> >> BTW, for all it is worth, any caching controller not using
> >> this is guaranteed to lose data.
> > 
> > Wrong layer.  You should be using the bus shutdown method; look at eg. 
> > the Mylex driver to see how this is done.  You should probably call your 
> > flush routine from the suspend method as well.
> This is dangerous for the OSM.  When the i2o OSM shuts an IOP
> down, it is history.  It will stop doing any work at all; network,
> disk, console, mouse, whatever.  I reserve that for really, really
> shutdown/reset.
> This needs to happen after all other shutdown work was done,
> but before a physical reset is sent to the hardware.
> There is no telling how long the IOP will take to return
> from flush request.

That is no problem.. you can take as long as you need.  The filesystems
are unmounted, all the system daemons have been shut down, all dirty
data has been pushed to the controller, sync(2) has happened.  The system
will do nothing else until your controller's shutdown method has returned.

If you want to reset it after doing the flush, there is nothing stopping
you - you can do it however you need to.

"All of this is for nothing if we don't go to the stars" - JMS/B5

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