Unused USB ports may have bogus location data in ACPI PLD tables. This causes port peering failures as these unused USB2 and USB3 ports location may match.
Due to these failures the driver prints a "usb: port power management may be unreliable" warning, and unnecessarily blocks port power off during runtime suspend.
This was debugged on a couple DELL systems where the unused ports all returned zeroes in their location data. Similar bugreports exist for other systems.
Don't try to peer or match ports that have connect type set to USB_PORT_NOT_USED.
Fixes: 3bfd659baec8 ("usb: find internal hub tier mismatch via acpi") Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218465 Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218486 Tested-by: Paul Menzel pmenzel@molgen.mpg.de Link: https://lore.kernel.org/linux-usb/5406d361-f5b7-4309-b0e6-8c94408f7d75@molge... Cc: stable@vger.kernel.org # v3.16+ Signed-off-by: Mathias Nyman mathias.nyman@linux.intel.com --- v1 -> v2 - Improve commit message - Add missing Fixes, Closes and Link tags - send this patch separately for easier picking to usb-linus
drivers/usb/core/port.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c index c628c1abc907..4d63496f98b6 100644 --- a/drivers/usb/core/port.c +++ b/drivers/usb/core/port.c @@ -573,7 +573,7 @@ static int match_location(struct usb_device *peer_hdev, void *p) struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev); struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);
- if (!peer_hub) + if (!peer_hub || port_dev->connect_type == USB_PORT_NOT_USED) return 0;
hcd = bus_to_hcd(hdev->bus); @@ -584,7 +584,8 @@ static int match_location(struct usb_device *peer_hdev, void *p)
for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) { peer = peer_hub->ports[port1 - 1]; - if (peer && peer->location == port_dev->location) { + if (peer && peer->connect_type != USB_PORT_NOT_USED && + peer->location == port_dev->location) { link_peers_report(port_dev, peer); return 1; /* done */ }