RE: [PATCH 1/4] PCI / ACPI: Identify external PCI devices

[Mario.Limonciello]

> -----Original Message-----
> From: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> Sent: Thursday, November 15, 2018 1:01 PM
> To: Lorenzo Pieralisi
> Cc: Lukas Wunner; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; Joerg Roedel; David
> Woodhouse; Lu Baolu; Ashok Raj; Bjorn Helgaas; Rafael J. Wysocki; Jacob jun Pan;
> Andreas Noever; Michael Jamet; Yehezkel Bernat; Christian Kellner; Limonciello,
> Mario; Anthony Wong; linux-acpi@xxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH 1/4] PCI / ACPI: Identify external PCI devices
> 
> 
> [EXTERNAL EMAIL]
> 
> On Thu, Nov 15, 2018 at 05:46:08PM +0000, Lorenzo Pieralisi wrote:
> > Do you really need to parse it if the dev->is_thunderbolt check is enough ?
> 
> Yes, we need to parse it one way or another. dev->is_thunderbolt is
> based on heuristics which do not apply anymore when the thing gets
> integrated in the SoC.
> 
> The _DSD is there already (on existing systems) and is being used by
> Windows so I don't understand why we cannot take advantage of it? Every
> new system with Thunderbolt ports will have it.

Furthermore it's entirely in the BIOS writers best interest to do this correctly
as it applies proper policy on Windows as well.

I wouldn't be surprised if WHCK failed if it was done wrong.