From 17f34867e98d2fb0c03918faab79efb989fa134b Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Thu, 23 May 2013 17:14:31 +0300 Subject: usb: add usb2 Link PM variables to sysfs and usb_device Adds abitilty to tune L1 timeout (inactivity timer for usb2 link sleep) and BESL (best effort service latency)via sysfs. This also adds a new usb2_lpm_parameters structure with those variables to struct usb_device. Signed-off-by: Mathias Nyman Signed-off-by: Sarah Sharp --- Documentation/ABI/testing/sysfs-bus-usb | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index f093e59cbe5..9759b8c9133 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -236,3 +236,30 @@ Description: This attribute is to expose these information to user space. The file will read "hotplug", "wired" and "not used" if the information is available, and "unknown" otherwise. + +What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout +Date: May 2013 +Contact: Mathias Nyman +Description: + USB 2.0 devices may support hardware link power management (LPM) + L1 sleep state. The usb2_lpm_l1_timeout attribute allows + tuning the timeout for L1 inactivity timer (LPM timer), e.g. + needed inactivity time before host requests the device to go to L1 sleep. + Useful for power management tuning. + Supported values are 0 - 65535 microseconds. + +What: /sys/bus/usb/devices/.../power/usb2_lpm_besl +Date: May 2013 +Contact: Mathias Nyman +Description: + USB 2.0 devices that support hardware link power management (LPM) + L1 sleep state now use a best effort service latency value (BESL) to + indicate the best effort to resumption of service to the device after the + initiation of the resume event. + If the device does not have a preferred besl value then the host can select + one instead. This usb2_lpm_besl attribute allows to tune the host selected besl + value in order to tune power saving and service latency. + + Supported values are 0 - 15. + More information on how besl values map to microseconds can be found in + USB 2.0 ECN Errata for Link Power Management, section 4.10) -- cgit v1.2.3-70-g09d2