Messages in this thread | | | Date | Mon, 13 May 2019 16:54:15 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH] nvme/pci: Use host managed power state for suspend |
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On Mon, May 13, 2019 at 02:43:43PM +0000, Mario.Limonciello@dell.com wrote: > Well I've got a thought, quoting the NVME spec: > "After a successful completion of a Set Features command for this feature, the controller shall be in the > Power State specified. If enabled, autonomous power state transitions continue to occur from the new state." > > If APST is enabled on this disk, what is to stop an autonomous reverse > transition from queue activity on the way down?
Nothing. But once the system is suspending we should not see I/O.
If we see I/O the queue freezing in the original patch Kai Heng and the previous one from Keith is probably required, although I suspect it just papers over problems higher up in the queue. If we don't see I/O the device is just behaving oddly.
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