diff options
Diffstat (limited to 'Documentation/ABI/testing/sysfs-bus-usb')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-usb | 116 |
1 files changed, 27 insertions, 89 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index f093e59cbe5f..1430f584b266 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -1,81 +1,3 @@ -What: /sys/bus/usb/devices/.../power/autosuspend -Date: March 2007 -KernelVersion: 2.6.21 -Contact: Alan Stern <stern@rowland.harvard.edu> -Description: - Each USB device directory will contain a file named - power/autosuspend. This file holds the time (in seconds) - the device must be idle before it will be autosuspended. - 0 means the device will be autosuspended as soon as - possible. Negative values will prevent the device from - being autosuspended at all, and writing a negative value - will resume the device if it is already suspended. - - The autosuspend delay for newly-created devices is set to - the value of the usbcore.autosuspend module parameter. - -What: /sys/bus/usb/devices/.../power/persist -Date: May 2007 -KernelVersion: 2.6.23 -Contact: Alan Stern <stern@rowland.harvard.edu> -Description: - If CONFIG_USB_PERSIST is set, then each USB device directory - will contain a file named power/persist. The file holds a - boolean value (0 or 1) indicating whether or not the - "USB-Persist" facility is enabled for the device. Since the - facility is inherently dangerous, it is disabled by default - for all devices except hubs. For more information, see - Documentation/usb/persist.txt. - -What: /sys/bus/usb/device/.../power/connected_duration -Date: January 2008 -KernelVersion: 2.6.25 -Contact: Sarah Sharp <sarah.a.sharp@intel.com> -Description: - If CONFIG_PM_RUNTIME is enabled then this file - is present. When read, it returns the total time (in msec) - that the USB device has been connected to the machine. This - file is read-only. -Users: - PowerTOP <power@bughost.org> - http://www.lesswatts.org/projects/powertop/ - -What: /sys/bus/usb/device/.../power/active_duration -Date: January 2008 -KernelVersion: 2.6.25 -Contact: Sarah Sharp <sarah.a.sharp@intel.com> -Description: - If CONFIG_PM_RUNTIME is enabled then this file - is present. When read, it returns the total time (in msec) - that the USB device has been active, i.e. not in a suspended - state. This file is read-only. - - Tools can use this file and the connected_duration file to - compute the percentage of time that a device has been active. - For example, - echo $((100 * `cat active_duration` / `cat connected_duration`)) - will give an integer percentage. Note that this does not - account for counter wrap. -Users: - PowerTOP <power@bughost.org> - http://www.lesswatts.org/projects/powertop/ - -What: /sys/bus/usb/device/<busnum>-<devnum>...:<config num>-<interface num>/supports_autosuspend -Date: January 2008 -KernelVersion: 2.6.27 -Contact: Sarah Sharp <sarah.a.sharp@intel.com> -Description: - When read, this file returns 1 if the interface driver - for this interface supports autosuspend. It also - returns 1 if no driver has claimed this interface, as an - unclaimed interface will not stop the device from being - autosuspended if all other interface drivers are idle. - The file returns 0 if autosuspend support has not been - added to the driver. -Users: - USB PM tool - git://git.moblin.org/users/sarah/usb-pm-tool/ - What: /sys/bus/usb/device/.../authorized Date: July 2008 KernelVersion: 2.6.26 @@ -172,17 +94,6 @@ Description: device IDs, exactly like reading from the entry "/sys/bus/usb/drivers/.../new_id" -What: /sys/bus/usb/device/.../avoid_reset_quirk -Date: December 2009 -Contact: Oliver Neukum <oliver@neukum.org> -Description: - Writing 1 to this file tells the kernel that this - device will morph into another mode when it is reset. - Drivers will not use reset for error handling for - such devices. -Users: - usb_modeswitch - What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm Date: September 2011 Contact: Andiry Xu <andiry.xu@amd.com> @@ -236,3 +147,30 @@ 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) |