Re: [PATCH] thunderbolt: Resume PCIe bridges after switch is found on AMD USB4 controller

From: Mika Westerberg
Date: Tue Sep 06 2022 - 12:02:28 EST


On Tue, Sep 06, 2022 at 05:59:49PM +0300, Mika Westerberg wrote:
> This reminded me that in Intel hardware there is an ACPI power resource that is
> shared between related devices. IIRC there is _PR0() method under the root
> port, xHCI and the TBT NHI that returns the same power resource. Now, when the
> power resource is turned on for any of the devices the kernel wakes up the rest
> too to make sure they get properly re-initialized if they went into
> D0unitialized or something like that. The commit that added this is
> 4533771c1e53 ("ACPI / PM: Introduce concept of a _PR0 dependent device").

Probably has nothing to do with this actually.