diff options
| author |   Lu Baolu <baolu.lu@linux.intel.com> | 2015-11-14 16:26:33 +0800 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-12-01 14:58:18 -0800 |
| commit | 513072d90a8dfe4bf83e1f81810de605eb5d7c3b (patch) | |
| tree | 101e668a61262a515b2ab8124f2d9ba568df7432 /Documentation/ABI | |
| parent | usb: core: lpm: fix usb3_hardware_lpm sysfs node (diff) | |
| download | linux-dev-513072d90a8dfe4bf83e1f81810de605eb5d7c3b.tar.xz linux-dev-513072d90a8dfe4bf83e1f81810de605eb5d7c3b.zip | |
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-usb | 11 |
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> |