Commit da9651a5d3d3bdb40e487e6f90f2e092a05f45b4
Committed by
Greg Kroah-Hartman
Greg Kroah-Hartman
1 parent
bb67490711
Exists in
smarc-imx_3.14.28_1.0.0_ga
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Documentation sysfs-bus-usb: Document all files used by libusb
Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Showing 1 changed file with 38 additions and 0 deletions Side-by-side Diff
Documentation/ABI/testing/sysfs-bus-usb
| ... | ... | @@ -263,4 +263,42 @@ |
| 263 | 263 | Supported values are 0 - 15. |
| 264 | 264 | More information on how besl values map to microseconds can be found in |
| 265 | 265 | USB 2.0 ECN Errata for Link Power Management, section 4.10) |
| 266 | + | |
| 267 | +What: /sys/bus/usb/devices/.../devnum | |
| 268 | +KernelVersion: since at least 2.6.18 | |
| 269 | +Description: | |
| 270 | + Device address on the USB bus. | |
| 271 | + | |
| 272 | +What: /sys/bus/usb/devices/.../bConfigurationValue | |
| 273 | +KernelVersion: since at least 2.6.18 | |
| 274 | +Description: | |
| 275 | + bConfigurationValue of the *active* configuration for the | |
| 276 | + device. Writing 0 or -1 to bConfigurationValue will reset the | |
| 277 | + active configuration (unconfigure the device). Writing | |
| 278 | + another value will change the active configuration. | |
| 279 | + | |
| 280 | + Note that some devices, in violation of the USB spec, have a | |
| 281 | + configuration with a value equal to 0. Writing 0 to | |
| 282 | + bConfigurationValue for these devices will install that | |
| 283 | + configuration, rather then unconfigure the device. | |
| 284 | + | |
| 285 | + Writing -1 will always unconfigure the device. | |
| 286 | + | |
| 287 | +What: /sys/bus/usb/devices/.../busnum | |
| 288 | +KernelVersion: 2.6.22 | |
| 289 | +Description: | |
| 290 | + Bus-number of the USB-bus the device is connected to. | |
| 291 | + | |
| 292 | +What: /sys/bus/usb/devices/.../descriptors | |
| 293 | +KernelVersion: 2.6.26 | |
| 294 | +Description: | |
| 295 | + Binary file containing cached descriptors of the device. The | |
| 296 | + binary data consists of the device descriptor followed by the | |
| 297 | + descriptors for each configuration of the device. | |
| 298 | + Note that the wTotalLength of the config descriptors can not | |
| 299 | + be trusted, as the device may have a smaller config descriptor | |
| 300 | + than it advertises. The bLength field of each (sub) descriptor | |
| 301 | + can be trusted, and can be used to seek forward one (sub) | |
| 302 | + descriptor at a time until the next config descriptor is found. | |
| 303 | + All descriptors read from this file are in bus-endian format |