143 lines
4.9 KiB
Plaintext
143 lines
4.9 KiB
Plaintext
What: /sys/bus/usb/devices/.../power/persist
|
|
Date: May 2007
|
|
KernelVersion: 2.6.23
|
|
Contact: Alan Stern <stern@rowland.harvard.edu>
|
|
Description:
|
|
USB device directories can 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. For
|
|
hubs this facility is always enabled and their device
|
|
directories will not contain this file.
|
|
|
|
For more information, see Documentation/driver-api/usb/persist.rst.
|
|
|
|
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/device/.../power/connected_duration
|
|
Date: January 2008
|
|
KernelVersion: 2.6.25
|
|
Contact: Sarah Sharp <sarah.a.sharp@intel.com>
|
|
Description:
|
|
If CONFIG_PM 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 <powertop@lists.01.org>
|
|
https://01.org/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 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 <powertop@lists.01.org>
|
|
https://01.org/powertop/
|
|
|
|
What: /sys/bus/usb/devices/<busnum>-<port[.port]>...:<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/.../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/.../devnum
|
|
KernelVersion: since at least 2.6.18
|
|
Description:
|
|
Device address on the USB bus.
|
|
Users:
|
|
libusb
|
|
|
|
What: /sys/bus/usb/devices/.../bConfigurationValue
|
|
KernelVersion: since at least 2.6.18
|
|
Description:
|
|
bConfigurationValue of the *active* configuration for the
|
|
device. Writing 0 or -1 to bConfigurationValue will reset the
|
|
active configuration (unconfigure the device). Writing
|
|
another value will change the active configuration.
|
|
|
|
Note that some devices, in violation of the USB spec, have a
|
|
configuration with a value equal to 0. Writing 0 to
|
|
bConfigurationValue for these devices will install that
|
|
configuration, rather then unconfigure the device.
|
|
|
|
Writing -1 will always unconfigure the device.
|
|
Users:
|
|
libusb
|
|
|
|
What: /sys/bus/usb/devices/.../busnum
|
|
KernelVersion: 2.6.22
|
|
Description:
|
|
Bus-number of the USB-bus the device is connected to.
|
|
Users:
|
|
libusb
|
|
|
|
What: /sys/bus/usb/devices/.../descriptors
|
|
KernelVersion: 2.6.26
|
|
Description:
|
|
Binary file containing cached descriptors of the device. The
|
|
binary data consists of the device descriptor followed by the
|
|
descriptors for each configuration of the device.
|
|
Note that the wTotalLength of the config descriptors can not
|
|
be trusted, as the device may have a smaller config descriptor
|
|
than it advertises. The bLength field of each (sub) descriptor
|
|
can be trusted, and can be used to seek forward one (sub)
|
|
descriptor at a time until the next config descriptor is found.
|
|
All descriptors read from this file are in bus-endian format
|
|
Users:
|
|
libusb
|
|
|
|
What: /sys/bus/usb/devices/.../speed
|
|
KernelVersion: since at least 2.6.18
|
|
Description:
|
|
Speed the device is connected with to the usb-host in
|
|
Mbit / second. IE one of 1.5 / 12 / 480 / 5000.
|
|
Users:
|
|
libusb
|