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From: Keith Busch <keith.busch@intel.com>
To: Sinan Kaya <okaya@codeaurora.org>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
	linux-pci@vger.kernel.org, timur@codeaurora.org,
	alex.williamson@redhat.com, vikrams@codeaurora.org,
	Lorenzo.Pieralisi@arm.com, linux-arm-msm@vger.kernel.org,
	linux-kernel@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH V4] PCI: handle CRS returned by device after FLR
Date: Thu, 13 Jul 2017 13:24:33 -0400	[thread overview]
Message-ID: <20170713172432.GB14716@localhost.localdomain> (raw)
In-Reply-To: <78020acc-c2b6-423c-38a0-251f86ffa8a9@codeaurora.org>

On Thu, Jul 13, 2017 at 12:42:44PM -0400, Sinan Kaya wrote:
> On 7/13/2017 12:29 PM, Keith Busch wrote:
> > That wording is just confusing. It looks to me the 1 second polling is
> > to be used following a reset if CRS is not implemented.
> > 
> >   https://pcisig.com/sites/default/files/specification_documents/ECN_RN_29_Aug_2013.pdf
> > 
> > "
> >   Through the mechanisms defined by this ECR, we can avoid the long,
> >   architected, fixed delays following various forms of reset before
> >   software is permitted to perform its first Configuration Request. These
> >   delays are very large:
> > 
> >   1 second if Configuration Retry Status (CRS) is not used
> > "
> > 
> > It goes on to say CRS is usually much lower, but doesn't specify an
> > upper bound either.
> > 
> 
> I see, we got caught on spec language where we don't know what 'its' is. 

Well, I don't know for certain if your original interpretation is
incorrect. Just saying the CRS intention doesn't explicitly stand out to me.

On a side note, I'll also see if I can get clarification on what
expectations the hardware people have for this particular product. Your
observation seems a little high to me, but I don't know if that's
outside the product's limits.

  reply	other threads:[~2017-07-13 17:24 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-06 21:07 [PATCH V4] PCI: handle CRS returned by device after FLR Sinan Kaya
2017-07-13 12:17 ` Bjorn Helgaas
2017-07-13 15:44   ` Sinan Kaya
2017-07-13 16:29     ` Keith Busch
2017-07-13 16:42       ` Sinan Kaya
2017-07-13 17:24         ` Keith Busch [this message]
2017-07-13 23:38     ` Bjorn Helgaas
2017-07-14 14:10       ` Sinan Kaya
2017-07-13 16:03   ` Keith Busch
2017-07-13 23:49 ` Bjorn Helgaas
2017-07-14 14:28   ` Sinan Kaya
2017-07-31 21:45   ` Sinan Kaya
2017-07-31 22:19     ` Bjorn Helgaas

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