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| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2013-05-23 18:14:31 +0400 |
|---|---|---|
| committer | Sarah Sharp <sarah.a.sharp@linux.intel.com> | 2013-06-06 03:48:40 +0400 |
| commit | 17f34867e98d2fb0c03918faab79efb989fa134b (patch) | |
| tree | 1ea3f266473f6d6aa7fec9a646e04158941d0a06 /Documentation/ABI/testing/sysfs-bus-usb | |
| parent | a558ccdcc71c7770c5e80c926a31cfe8a3892a09 (diff) | |
| download | linux-17f34867e98d2fb0c03918faab79efb989fa134b.tar.xz | |
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 <mathias.nyman@linux.intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Diffstat (limited to 'Documentation/ABI/testing/sysfs-bus-usb')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-usb | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index f093e59cbe5f..9759b8c91332 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 <mathias.nyman@linux.intel.com> +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 <mathias.nyman@linux.intel.com> +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) |