diff options
Diffstat (limited to 'Documentation/ABI/testing/sysfs-bus-usb')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-usb | 144 |
1 files changed, 52 insertions, 92 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index 5f75f8f7df3..614d451cee4 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 and CONFIG_USB_SUSPEND are 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 and CONFIG_USB_SUSPEND are 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 @@ -128,13 +50,19 @@ Description: This may allow the driver to support more hardware than was included in the driver's static device ID support table at compile time. The format for the device ID is: - idVendor idProduct bInterfaceClass. + idVendor idProduct bInterfaceClass RefIdVendor RefIdProduct The vendor ID and device ID fields are required, the - interface class is optional. + rest is optional. The Ref* tuple can be used to tell the + driver to use the same driver_data for the new device as + it is used for the reference device. Upon successfully adding an ID, the driver will probe for the device and attempt to bind to it. For example: # echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id + Here add a new device (0458:7045) using driver_data from + an already supported device (0458:704c): + # echo "0458 7045 0 0458 704c" > /sys/bus/usb/drivers/foo/new_id + Reading from this file will list all dynamically added device IDs in the same format, with one entry per line. For example: @@ -172,22 +100,11 @@ 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> Description: - If CONFIG_USB_SUSPEND is set and a USB 2.0 lpm-capable device + If CONFIG_PM_RUNTIME is set and a USB 2.0 lpm-capable device is plugged in to a xHCI host which support link PM, it will perform a LPM test; if the test is passed and host supports USB2 hardware LPM (xHCI 1.0 feature), USB2 hardware LPM will @@ -220,3 +137,46 @@ Description: If the device doesn't support LTM, the file will read "no". The file will be present for all speeds of USB devices, and will always read "no" for USB 1.1 and USB 2.0 devices. + +What: /sys/bus/usb/devices/.../(hub interface)/portX +Date: August 2012 +Contact: Lan Tianyu <tianyu.lan@intel.com> +Description: + The /sys/bus/usb/devices/.../(hub interface)/portX + is usb port device's sysfs directory. + +What: /sys/bus/usb/devices/.../(hub interface)/portX/connect_type +Date: January 2013 +Contact: Lan Tianyu <tianyu.lan@intel.com> +Description: + Some platforms provide usb port connect types through ACPI. + 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) |