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Diffstat (limited to 'Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd b/Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd new file mode 100644 index 000000000000..0088aba4caa8 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd @@ -0,0 +1,25 @@ +What: /sys/bus/pci/drivers/xhci_hcd/.../dbc +Date: June 2017 +Contact: Lu Baolu <baolu.lu@linux.intel.com> +Description: + xHCI compatible USB host controllers (i.e. super-speed + USB3 controllers) are often implemented with the Debug + Capability (DbC). It can present a debug device which + is fully compliant with the USB framework and provides + the equivalent of a very high performance full-duplex + serial link for debug purpose. + + The DbC debug device shares a root port with xHCI host. + When the DbC is enabled, the root port will be assigned + to the Debug Capability. Otherwise, it will be assigned + to xHCI. + + Writing "enable" to this attribute will enable the DbC + functionality and the shared root port will be assigned + to the DbC device. Writing "disable" to this attribute + will disable the DbC functionality and the shared root + port will roll back to the xHCI. + + Reading this attribute gives the state of the DbC. It + can be one of the following states: disabled, enabled, + initialized, connected, configured and stalled. |