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From: Alex Williamson <alex.williamson@redhat.com>
To: Sinan Kaya <okaya@kernel.org>
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-nvme@lists.infradead.org
Subject: Re: [PATCH v2 2/2] PCI: NVMe device specific reset quirk
Date: Mon, 23 Jul 2018 19:57:11 -0600	[thread overview]
Message-ID: <20180723195711.0a3c9301@t450s.home> (raw)
In-Reply-To: <abc86e6b-7df5-a84c-7e98-107c605812c6@kernel.org>

On Mon, 23 Jul 2018 17:40:02 -0700
Sinan Kaya <okaya@kernel.org> wrote:

> On 7/23/2018 5:13 PM, Alex Williamson wrote:
> > + * The NVMe specification requires that controllers support PCIe FLR, but
> > + * but some Samsung SM961/PM961 controllers fail to recover after FLR (-1
> > + * config space) unless the device is quiesced prior to FLR.  
> 
> Does disabling the memory bit in PCI config space as part of the FLR 
> reset function help? (like the very first thing)

No, it does not.  I modified this to only clear PCI_COMMAND_MEMORY and
call pcie_flr(), the Samsung controller dies just as it did previously.
 
> Can we do that in the pcie_flr() function to cover other endpoint types
> that might be pushing traffic while code is trying to do a reset?

Do you mean PCI_COMMAND_MASTER rather than PCI_COMMAND_MEMORY?  I tried
that too, it doesn't work either.  I'm not really sure the theory
behind clearing memory, clearing busmaster to stop DMA seems like a
sane thing to do, but doesn't help here.  Thanks,

Alex

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  reply	other threads:[~2018-07-24  1:57 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-24  0:12 [PATCH v2 0/2] PCI: NVMe reset quirk Alex Williamson
2018-07-24  0:13 ` [PATCH v2 1/2] PCI: Export pcie_has_flr() Alex Williamson
2018-07-24  0:13 ` [PATCH v2 2/2] PCI: NVMe device specific reset quirk Alex Williamson
2018-07-24  0:40   ` Sinan Kaya
2018-07-24  1:57     ` Alex Williamson [this message]
2018-07-24  2:20       ` Sinan Kaya
2018-07-24  3:16         ` Alex Williamson
2018-07-24  6:54   ` Christoph Hellwig

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