Re: [PATCH 0/2] Mark USB4 controllers as is_thunderbolt

Mika Westerberg
2022-02-07T07:04:48Z

Hi Mario,

On Fri, Feb 04, 2022 at 12:28:18PM -0600, Mario Limonciello wrote:
> Various drivers in the kernel use `pci_is_thunderbolt_attached` to
> designate behaving differently from a device that is internally in
> the machine. This function relies upon the `is_thunderbolt` designation
> which checks for a specific capability only set on Intel controllers.
>
> Non-Intel USB4 designs should also match this designation so that they
> can be treated the same regardless of the host they're connected to.

Not objecting this if really needed but since USB4 is supposed to be
transparent to the native (tunneled) protocol, I would rather try to
figure out if there is really need to change driver behaviour whether it
is connected over USB4 or plugged natively on the PCIe slot.

Can you elaborate a bit what kind of functionality needs this? Perhaps
we can figure a better alternative?

Thanks!