Messages in this thread |  | | | Date | Wed, 02 Jan 2008 13:57:41 -0500 | | From | Jeff Garzik <> | | Subject | Re: sata_nv + ADMA + Samsung disk problem |
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Allen Martin wrote: >> The question I had for NVIDIA regarding this that I never got >> answered >> was, is there any reason why we would need a delay when switching >> between NCQ and non-NCQ commands on ADMA, and if not, is >> there any known >> cause that could cause the controller to get into this seemingly >> locked-up state? > > When switching from NCQ to non NCQ or vice versa you must make sure all > outstanding commands are completed before issuing the new command. The > hardware doesn't do anything to prevent queued and non queued commands > from going out on the wire at the same time which will certainly cause > some drives to fail.
The software definitely provides that guarantee for all NCQ-capable controllers.
Jeff
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