path: root/Documentation/ABI/testing/sysfs-bus-usb
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Diffstat (limited to 'Documentation/ABI/testing/sysfs-bus-usb')
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 6df4e6f5756..5f75f8f7df3 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -208,3 +208,15 @@ Description:
such as ACPI. This file will read either "removable" or
"fixed" if the information is available, and "unknown"
+What: /sys/bus/usb/devices/.../ltm_capable
+Date: July 2012
+Contact: Sarah Sharp <>
+ USB 3.0 devices may optionally support Latency Tolerance
+ Messaging (LTM). They indicate their support by setting a bit
+ in the bmAttributes field of their SuperSpeed BOS descriptors.
+ If that bit is set for the device, ltm_capable will read "yes".
+ If the device doesn't support LTM, the file will read "no".
+ The file will be present for all speeds of USB devices, and will
+ always read "no" for USB 1.1 and USB 2.0 devices.