On Wed, Jul 13, 2016 at 12:17:33AM +0200, Andreas Noever wrote: > Are thunderbolt controllers always installed directly below the root > port? In theory there could be more bridges in between (a candidate > for such a topology would be the mac pro which has 3 controllers). Hm, good point. I failed to find lspci or dmesg output for a MacPro6,1 but I did find this diagram: http://i.imgur.com/ItIqxDY.png Turns out the 3 controllers are connected to a PCIe switch. And according to the PCIe spec, a switch consists of an upstream bridge and downstream bridges. So the parent of the Thunderbolt upstream port would be a downstream port and not a root port. :-/ Another idea would be to detect if the parent of the Thunderbolt upstream port has the VSEC 0x1234. This is only present on Thunderbolt devices, so a host controller is identifiable by the non-presence of that VSEC on its parent. Patch [01/13] of my runpm series adds a convenient is_thunderbolt flag to detect the VSEC: https://github.com/l1k/linux/commit/8148c395ef6e Generally I think it would be beneficial to replace the PCI quirk with code that lives in drivers/thunderbolt/. Here's an example what I have in mind, this is based on top of the runpm series and ensures that the NHI resumes before the hotplug ports by waking it directly from the upstream bridge: https://github.com/l1k/linux/commit/c596932608cd An even better approach would probably be Rafael's "device links" series which allows the PM core to take care of device dependencies beyond the mere parent/child relationship: https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg1170039.html Best regards, Lukas -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
