[PATCH] NVMe: Re-introduce polling for completions

[Keith Busch]

On Tue, Apr 05, 2016 at 10:04:22PM +0000, Judy Brock-SSI wrote:
> Going straight to MSI-x is a higher risk change since re-introducing polling restores code that was in place previously with no reported problems whereas changing the init path to something new has no test time on it.

Well, I wouldn't say "no" test time since we have a well tested path
that goes straight to MSI-x in place for some time.

If we rely on polled completions during initialization, we potentially
add up to 2 seconds for device initialization to complete (1 second
polling interval * 2 commands using broken IRQ).

Maybe you want both?