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SubjectRe: [PATCH V2] PCI: Do not enable extended tags on pre-dated (v1.x) systems
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 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.

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