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Date: Fri, 21 Apr 2017 03:54:46 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Jens Axboe <axboe@fb.com>
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Subject: Re: [PATCH 0/4] blk-mq-sched: allow to use hw tag for sched
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On Thu, Apr 20, 2017 at 10:10:59AM -0600, Jens Axboe wrote:
> Right, the hardware doesn't require it at all, it's just an oddity
> of the driver that it hardwares tag 0 as an internal tag. That could
> definitely get cleaned up.

That's exactly what I suspect, especially as the hardware is AHCI
on stereoids.  But I'd need a data sheet to confirm my suspicion.