From: Keith Busch <kbusch@kernel.org>
To: Austin.Bolen@dell.com
Cc: hch@infradead.org, Alex_Gagniuc@Dellteam.com,
torvalds@linux-foundation.org, keith.busch@intel.com,
sagi@grimberg.me, linux-kernel@vger.kernel.org,
linux-nvme@lists.infradead.org, axboe@fb.com,
mr.nuke.me@gmail.com, hch@lst.de, jonathan.derrick@intel.com
Subject: Re: [PATCH] nvme-pci: Prevent mmio reads if pci channel offline
Date: Thu, 28 Feb 2019 17:30:26 -0700 [thread overview]
Message-ID: <20190301003026.GA22712@localhost.localdomain> (raw)
In-Reply-To: <680f55f95e7547bdaffddce49772a5b7@AUSX13MPC131.AMER.DELL.COM>
On Thu, Feb 28, 2019 at 11:43:46PM +0000, Austin.Bolen@dell.com wrote:
> On 2/28/2019 5:20 PM, Keith Busch wrote:
> > SBR and Link Disable are done from the down stream port, though, so the
> > host can still communicate with the function that took the link down.
> > That's entirely different than taking the link down from the end device,
> > so I'm not sure how NVMe can fix that.
> >
>
> Agreed it is different. Here is one way they could have solved it: host
> writes magic value to NSSRC but device latches this instead of
> resetting. Then require host to do SBR. When device sees SBR with
> magic value in NSSRC it does an NSSR.
For single port drives, yes, but that wouldn't work so well for multi-port
devices connected to different busses, maybe even across multiple hosts.
The equivalent of an FLR across all ports should have been sufficient,
IMO.
next prev parent reply other threads:[~2019-03-01 0:30 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-22 1:05 [PATCH] nvme-pci: Prevent mmio reads if pci channel offline Jon Derrick
2019-02-22 21:28 ` Linus Torvalds
2019-02-22 21:59 ` Keith Busch
2019-02-24 20:37 ` Alex_Gagniuc
2019-02-24 22:42 ` Linus Torvalds
2019-02-24 23:27 ` Alex_Gagniuc
2019-02-25 0:43 ` Linus Torvalds
2019-02-25 15:55 ` Keith Busch
2019-02-26 22:37 ` Alex_Gagniuc
2019-02-27 1:01 ` Linus Torvalds
2019-02-27 16:42 ` Alex_Gagniuc
2019-02-27 17:51 ` Keith Busch
2019-02-27 18:07 ` Alex_Gagniuc
2019-02-27 17:55 ` Austin.Bolen
2019-02-27 20:04 ` Austin.Bolen
2019-02-28 14:16 ` Christoph Hellwig
2019-02-28 23:10 ` Austin.Bolen
2019-02-28 23:20 ` Keith Busch
2019-02-28 23:43 ` Austin.Bolen
2019-03-01 0:30 ` Keith Busch [this message]
2019-03-01 1:52 ` Austin.Bolen
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