From: David Fugate <david.fugate@linux.intel.com>
To: Keith Busch <kbusch@kernel.org>
Cc: axboe@fb.com, david.fugate@intel.com,
Christoph Hellwig <hch@lst.de>,
linux-nvme@lists.infradead.org, sagi@grimberg.me
Subject: Re: [PATCH] nvme: associate stripe size quirk with D4512
Date: Thu, 02 Jul 2020 16:26:21 -0600 [thread overview]
Message-ID: <50b54887cbd5944cd3a24a57e806f2d2f694339c.camel@linux.intel.com> (raw)
In-Reply-To: <20200702214830.GB1990925@dhcp-10-100-145-180.wdl.wdc.com>
On Thu, 2020-07-02 at 14:48 -0700, Keith Busch wrote:
> On Thu, Jul 02, 2020 at 03:16:04PM -0600, David Fugate wrote:
> > Did hear from our D4512 team there are concerns with this drive
> > advertising itself as NVMe 1.2 compliant while also implementing
> > aspects of NVMe 1.3 such as NOIOB. Of course the Linux NVMe driver
> > does the right thing in terms of ignoring the drive-reported spec
> > compliance value in favor of feature detection. Can't be certain
> > that's the case with all other OSes and closed-source drivers
> > in particular.
>
> I don't understand this concern. If a driver fails to detect a
> feature,
> then they're in the exact same situation as if the controller didn't
> implement it.
Imagine a less-enlightened NVMe driver which guards enablement of
features based *both* on the NVMe spec version the controller reports
as well as feature detection. In such cases, it wouldn't matter if a
drive implemented NOIOB (NVMe 1.3) if the controller advertises itself
as 1.2. E.g., same general type of version-checking logic as
implemented by nvme_report_ns_ids, but expanded to something that
actually *is* detectable as a feature. Linux does the right thing as
well as Intel-authored NVMe drivers I'm familiar with. Can't say this
for closed-source drivers though, and that was the concern given.
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next prev parent reply other threads:[~2020-07-02 22:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-11 3:38 [PATCH] nvme: associate stripe size quirk with D4512 David Fugate
2020-06-11 5:41 ` Christoph Hellwig
2020-06-12 14:43 ` David Fugate
2020-06-15 7:20 ` Christoph Hellwig
2020-07-02 21:16 ` David Fugate
2020-07-02 21:48 ` Keith Busch
2020-07-02 22:26 ` David Fugate [this message]
2020-07-03 20:16 ` Keith Busch
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