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authorBjørn Mork <bjorn@mork.no>2018-09-28 15:40:31 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-10-02 21:05:30 +0200
commit355c74e55e9992126ec5e568a3edb8e280fe040d (patch)
tree0d45517642de599088dede57dc0d51144edbc25e /Documentation/ABI
parentusb: hub: try old enumeration scheme first for high speed devices (diff)
downloadlinux-355c74e55e9992126ec5e568a3edb8e280fe040d.tar.xz
linux-355c74e55e9992126ec5e568a3edb8e280fe040d.zip
usb: export firmware port location in sysfs
The platform firmware "location" data is used to find port peer relationships. But firmware is an unreliable source, and there are real world examples of errors leading to missing or wrong peer relationships. Debugging this is currently hard. Exporting the location attribute makes it easier to spot mismatches between the firmware data and the real world. Signed-off-by: Bjørn Mork <bjorn@mork.no> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/ABI')
-rw-r--r--Documentation/ABI/testing/sysfs-bus-usb10
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index c4a70f532ec3..559baa5c418c 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -189,6 +189,16 @@ Description:
The file will read "hotplug", "wired" and "not used" if the
information is available, and "unknown" otherwise.
+What: /sys/bus/usb/devices/.../(hub interface)/portX/location
+Date: October 2018
+Contact: Bjørn Mork <bjorn@mork.no>
+Description:
+ Some platforms provide usb port physical location through
+ firmware. This is used by the kernel to pair up logical ports
+ mapping to the same physical connector. The attribute exposes the
+ raw location value as a hex integer.
+
+
What: /sys/bus/usb/devices/.../(hub interface)/portX/quirks
Date: May 2018
Contact: Nicolas Boichat <drinkcat@chromium.org>