From: Sinan Kaya <okaya@codeaurora.org>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: linux-pci@vger.kernel.org, timur@codeaurora.org,
wim.ten.have@oracle.com, linux-arm-msm@vger.kernel.org,
Bjorn Helgaas <bhelgaas@google.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH V2] PCI: Do not enable extended tags on pre-dated (v1.x) systems
Date: Mon, 10 Jul 2017 20:20:49 -0400 [thread overview]
Message-ID: <5f5119fd-64d5-5e7c-fa50-54ac6e6a36b6@codeaurora.org> (raw)
In-Reply-To: <20170710230911.GH5610@bhelgaas-glaptop.roam.corp.google.com>
Hi Bjorn,
On 7/10/2017 7:09 PM, Bjorn Helgaas wrote:
> The PCI_EXP_DEVCTL_EXT_TAG bit controls the behavior of the function as a
> Requester. As far as I can see, it has nothing to do with whether the
> function supports 8-bit tags as a *Completer*, so the implicit assumption
> of the spec is that all Completers always support 8-bit tags. My guess is
> that's why the ECN thought it would be safe to enable extended tags by
> default.
>
> If that's the case, this is just a defect in the device (the Completer),
> and we should blacklist it. Looking at the PCIe Capability version might
> happen to correlate with Completer support for 8-bit tags, but that looks
> like just a coincidence to me.
Sure, I can change to blacklist. I'll not enable it unless the device is blacklisted
via quirks.
Sinan
--
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
next prev parent reply other threads:[~2017-07-11 0:20 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-07 14:53 [PATCH V2] PCI: Do not enable extended tags on pre-dated (v1.x) systems Sinan Kaya
2017-07-07 15:01 ` Sinan Kaya
2017-07-07 16:08 ` Wim ten Have
2017-07-07 15:07 ` Sinan Kaya
2017-07-07 15:22 ` Sinan Kaya
2017-07-10 23:09 ` Bjorn Helgaas
2017-07-11 0:20 ` Sinan Kaya [this message]
2017-07-11 1:41 ` Sinan Kaya
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