Re: [t13] RE: comment on T10 ATA-passthru

[Andy Warner <andyw@pobox.com>]

Jeff Garzik wrote:
> [I ask about NCQ ...]
> Most of the code is already written to assume that queueing is
> active.  Turning on NCQ in libata is trivial.  Handling errors and
> synchronization is less trivial :)

I guess I'm a little gun shy here :) Remember, my induction to
hotplug consisted of:

	"That's because libata doesn't call the proper hot-unplug hooks.
	 Call those hooks, and the problem goes away."

I really don't want to hugely underestimate the effort involved.

Things that I can't quite see being in there right now
are the low-level state machine support for queued events,
and data structures and functions required to queue the pending
requests.

The boundary conditions you allude to seem likely to be
a pandora's box. Not the least of which will be ensuring
that queued and non-queued commands never mingle. It is
my understanding that any non-queued command will abort
*all* pending queued commands with unpredictable results
for data in flight.

What (if any) chip/board level driver work can be expected ?
-- 
andyw@pobox.com

Andy Warner		Voice: (612) 801-8549	Fax: (208) 575-5634