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authorLu Baolu <baolu.lu@linux.intel.com>2015-11-14 11:26:33 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-12-02 01:58:18 +0300
commit513072d90a8dfe4bf83e1f81810de605eb5d7c3b (patch)
tree101e668a61262a515b2ab8124f2d9ba568df7432 /Documentation/ABI
parentbf5ce5bf3cc7136fd7fe5e8999a580bc93a9c8f6 (diff)
downloadlinux-513072d90a8dfe4bf83e1f81810de605eb5d7c3b.tar.xz
usb: core: lpm: add sysfs node for usb3 lpm permit
USB3 LPM is default on in Linux kernel if both xHCI host controller and the USB devices declare to be LPM-capable. Unfortunately, some devices are known to work well with LPM disabled, but to be broken if LPM is enabled, although it declares the LPM capability. Users won't be able to use this kind of devices, until someone puts them in the kernel blacklist and gets the kernel upgraded. This patch adds a sysfs node to permit or forbit USB3 LPM U1 or U2 entry for a port. The settings apply to both before and after device enumeration. Supported values are "0" - neither u1 nor u2 permitted, "u1" - only u1 is permitted, "u2" - only u2 is permitted, "u1_u2" - both u1 and u2 are permitted. With this interface, users can use an LPM-unfriendly USB device on a released Linux kernel. Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Zhuang Jin Can <jin.can.zhuang@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/ABI')
-rw-r--r--Documentation/ABI/testing/sysfs-bus-usb11
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 136ba17d2da0..0bd731cbb50c 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -189,6 +189,17 @@ 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/usb3_lpm_permit
+Date: November 2015
+Contact: Lu Baolu <baolu.lu@linux.intel.com>
+Description:
+ Some USB3.0 devices are not friendly to USB3 LPM. usb3_lpm_permit
+ attribute allows enabling/disabling usb3 lpm of a port. It takes
+ effect both before and after a usb device is enumerated. Supported
+ values are "0" if both u1 and u2 are NOT permitted, "u1" if only u1
+ is permitted, "u2" if only u2 is permitted, "u1_u2" if both u1 and
+ u2 are permitted.
+
What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout
Date: May 2013
Contact: Mathias Nyman <mathias.nyman@linux.intel.com>