2023-08-30 17:31:07 +02:00
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What: /sys/bus/pci/drivers/xhci_hcd/.../dbc
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Date: June 2017
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Contact: Lu Baolu <baolu.lu@linux.intel.com>
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Description:
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xHCI compatible USB host controllers (i.e. super-speed
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USB3 controllers) are often implemented with the Debug
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Capability (DbC). It can present a debug device which
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is fully compliant with the USB framework and provides
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the equivalent of a very high performance full-duplex
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serial link for debug purpose.
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The DbC debug device shares a root port with xHCI host.
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When the DbC is enabled, the root port will be assigned
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to the Debug Capability. Otherwise, it will be assigned
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to xHCI.
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Writing "enable" to this attribute will enable the DbC
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functionality and the shared root port will be assigned
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to the DbC device. Writing "disable" to this attribute
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will disable the DbC functionality and the shared root
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port will roll back to the xHCI.
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Reading this attribute gives the state of the DbC. It
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can be one of the following states: disabled, enabled,
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initialized, connected, configured and stalled.
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2023-10-24 12:59:35 +02:00
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What: /sys/bus/pci/drivers/xhci_hcd/.../dbc_idVendor
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Date: March 2023
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Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
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Description:
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This dbc_idVendor attribute lets us change the idVendor field
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presented in the USB device descriptor by this xhci debug
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device.
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Value can only be changed while debug capability (DbC) is in
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disabled state to prevent USB device descriptor change while
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connected to a USB host.
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The default value is 0x1d6b (Linux Foundation).
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It can be any 16-bit integer.
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What: /sys/bus/pci/drivers/xhci_hcd/.../dbc_idProduct
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Date: March 2023
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Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
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Description:
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This dbc_idProduct attribute lets us change the idProduct field
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presented in the USB device descriptor by this xhci debug
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device.
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Value can only be changed while debug capability (DbC) is in
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disabled state to prevent USB device descriptor change while
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connected to a USB host.
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The default value is 0x0010. It can be any 16-bit integer.
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What: /sys/bus/pci/drivers/xhci_hcd/.../dbc_bcdDevice
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Date: March 2023
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Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
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Description:
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This dbc_bcdDevice attribute lets us change the bcdDevice field
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presented in the USB device descriptor by this xhci debug
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device.
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Value can only be changed while debug capability (DbC) is in
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disabled state to prevent USB device descriptor change while
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connected to a USB host.
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The default value is 0x0010. (device rev 0.10)
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It can be any 16-bit integer.
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What: /sys/bus/pci/drivers/xhci_hcd/.../dbc_bInterfaceProtocol
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Date: March 2023
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Contact: Mathias Nyman <mathias.nyman@linux.intel.com>
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Description:
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This attribute lets us change the bInterfaceProtocol field
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presented in the USB Interface descriptor by the xhci debug
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device.
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Value can only be changed while debug capability (DbC) is in
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disabled state to prevent USB descriptor change while
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connected to a USB host.
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The default value is 1 (GNU Remote Debug command).
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Other permissible value is 0 which is for vendor defined debug
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target.
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