linux/drivers/usb/core
Don Zickus 6406eeb3f5 usb: Quiet down false peer failure messages
My recent Intel box is spewing these messages:

xhci_hcd 0000:00:14.0: xHCI Host Controller
xhci_hcd 0000:00:14.0: new USB bus registered, assigned bus number 2
usb usb2: New USB device found, idVendor=1d6b, idProduct=0003
usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1
usb usb2: Product: xHCI Host Controller
usb usb2: Manufacturer: Linux 4.3.0+ xhci-hcd
usb usb2: SerialNumber: 0000:00:14.0
hub 2-0:1.0: USB hub found
hub 2-0:1.0: 6 ports detected
usb: failed to peer usb2-port2 and usb1-port1 by location (usb2-port2:none) (usb1-port1:usb2-port1)
usb usb2-port2: failed to peer to usb1-port1 (-16)
usb: port power management may be unreliable
usb: failed to peer usb2-port3 and usb1-port1 by location (usb2-port3:none) (usb1-port1:usb2-port1)
usb usb2-port3: failed to peer to usb1-port1 (-16)
usb: failed to peer usb2-port5 and usb1-port1 by location (usb2-port5:none) (usb1-port1:usb2-port1)
usb usb2-port5: failed to peer to usb1-port1 (-16)
usb: failed to peer usb2-port6 and usb1-port1 by location (usb2-port6:none) (usb1-port1:usb2-port1)
usb usb2-port6: failed to peer to usb1-port1 (-16)

Diving into the acpi tables, I noticed the EHCI hub has 12 ports while the XHCI
hub has 8 ports.  Most of those ports are of connect type USB_PORT_NOT_USED
(including port 1 of the EHCI hub).

Further the unused ports have location data initialized to 0x80000000.

Now each unused port on the xhci hub walks the port list and finds a matching
peer with port1 of the EHCI hub because the zero'd out group id bits falsely match.
After port1 of the XHCI hub, each following matching peer will generate the
above warning.

These warnings seem to be harmless for this scenario as I don't think it
matters that unused ports could not create a peer link.

The attached patch utilizes that assumption and just turns the pr_warn into
pr_debug to quiet things down.

Tested on my Intel box.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-12-04 08:19:55 -08:00
..
buffer.c Usb: core: buffer: fixed the checkpatch warning 2015-05-10 15:44:10 +02:00
config.c usb: Use the USB_SS_MULT() macro to decode burst multiplier for log message 2015-12-01 14:45:52 -08:00
devices.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
devio.c usb: devio: fix spacing 2015-08-08 15:17:17 -07:00
driver.c usb: core: driver: Use kmalloc_array 2015-10-04 10:47:19 +01:00
endpoint.c usb: endpoint: convert spaces to tabs 2015-08-14 16:50:36 -07:00
file.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-11-13 15:34:18 +09:00
generic.c staging: usbip: convert usbip-host driver to usb_device_driver 2014-02-07 10:54:30 -08:00
hcd-pci.c USB / PM: Drop CONFIG_PM_RUNTIME from the USB core 2014-12-04 00:51:54 +01:00
hcd.c usb: hcd: use USB_DT_* 2015-10-16 23:40:06 -07:00
hub.c usb: core : hub: Fix BOS 'NULL pointer' kernel panic 2015-12-01 14:45:52 -08:00
hub.h usb: hub: convert khubd into workqueue 2014-09-23 22:33:19 -07:00
Kconfig usb: kconfig: fix warning of select USB_OTG 2015-11-19 16:31:42 -08:00
Makefile USB: core: remove CONFIG_USB_DEBUG usage 2013-12-21 16:01:00 -08:00
message.c usb: message: remove redundant declaration 2015-10-04 10:45:11 +01:00
notify.c usb: Add export.h for EXPORT_SYMBOL/THIS_MODULE where needed 2011-10-31 19:31:25 -04:00
otg_whitelist.h usb: otg_whitelist: remove whitespace 2015-08-14 16:50:36 -07:00
port.c usb: Quiet down false peer failure messages 2015-12-04 08:19:55 -08:00
quirks.c USB: quirks: Fix another ELAN touchscreen 2015-12-01 10:23:33 -08:00
sysfs.c usb: interface authorization: SysFS part of USB interface authorization 2015-09-22 12:08:40 -07:00
urb.c USB: core: Codestyle fix in urb.c 2015-10-26 04:04:48 +09:00
usb-acpi.c usb: find internal hub tier mismatch via acpi 2014-05-27 16:38:52 -07:00
usb.c usb: interface authorization: Use a flag for the default device authorization 2015-09-22 12:08:40 -07:00
usb.h usb: interface authorization: Introduces the USB interface authorization 2015-09-22 12:08:40 -07:00