Merge branch 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb (1be025d3) · Commits · 戴 / test

Documentation/ABI/testing/sysfs-bus-pci-drivers-ehci_hcd

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		What: /sys/bus/pci/drivers/ehci_hcd/.../companion
		/sys/bus/usb/devices/usbN/../companion
		Date: January 2007
		KernelVersion: 2.6.21
		Contact: Alan Stern <stern@rowland.harvard.edu>
		Description:
		PCI-based EHCI USB controllers (i.e., high-speed USB-2.0
		controllers) are often implemented along with a set of
		"companion" full/low-speed USB-1.1 controllers. When a
		high-speed device is plugged in, the connection is routed
		to the EHCI controller; when a full- or low-speed device
		is plugged in, the connection is routed to the companion
		controller.

		Sometimes you want to force a high-speed device to connect
		at full speed, which can be accomplished by forcing the
		connection to be routed to the companion controller.
		That's what this file does. Writing a port number to the
		file causes connections on that port to be routed to the
		companion controller, and writing the negative of a port
		number returns the port to normal operation.

		For example: To force the high-speed device attached to
		port 4 on bus 2 to run at full speed:

		echo 4 >/sys/bus/usb/devices/usb2/../companion

		To return the port to high-speed operation:

		echo -4 >/sys/bus/usb/devices/usb2/../companion

		Reading the file gives the list of ports currently forced
		to the companion controller.

		Note: Some EHCI controllers do not have companions; they
		may contain an internal "transaction translator" or they
		may be attached directly to a "rate-matching hub". This
		mechanism will not work with such controllers. Also, it
		cannot be used to force a port on a high-speed hub to
		connect at full speed.

		Note: When this file was first added, it appeared in a
		different sysfs directory. The location given above is
		correct for 2.6.35 (and probably several earlier kernel
		versions as well).

Documentation/ABI/testing/sysfs-bus-usb

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		@@ -142,3 +142,18 @@ Description:
		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
		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
		be enabled for the device and the USB device directory will
		contain a file named power/usb2_hardware_lpm. The file holds
		a string value (enable or disable) indicating whether or not
		USB2 hardware LPM is enabled for the device. Developer can
		write y/Y/1 or n/N/0 to the file to enable/disable the
		feature.

Documentation/usb/dwc3.txt

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		TODO
		~~~~~~
		Please pick something while reading :)

		- Convert interrupt handler to per-ep-thread-irq

		As it turns out some DWC3-commands ~1ms to complete. Currently we spin
		until the command completes which is bad.

		Implementation idea:
		- dwc core implements a demultiplexing irq chip for interrupts per
		endpoint. The interrupt numbers are allocated during probe and belong
		to the device. If MSI provides per-endpoint interrupt this dummy
		interrupt chip can be replaced with "real" interrupts.
		- interrupts are requested / allocated on usb_ep_enable() and removed on
		usb_ep_disable(). Worst case are 32 interrupts, the lower limit is two
		for ep0/1.
		- dwc3_send_gadget_ep_cmd() will sleep in wait_for_completion_timeout()
		until the command completes.
		- the interrupt handler is split into the following pieces:
		- primary handler of the device
		goes through every event and calls generic_handle_irq() for event
		it. On return from generic_handle_irq() in acknowledges the event
		counter so interrupt goes away (eventually).

		- threaded handler of the device
		none

		- primary handler of the EP-interrupt
		reads the event and tries to process it. Everything that requries
		sleeping is handed over to the Thread. The event is saved in an
		per-endpoint data-structure.
		We probably have to pay attention not to process events once we
		handed something to thread so we don't process event X prio Y
		where X > Y.

		- threaded handler of the EP-interrupt
		handles the remaining EP work which might sleep such as waiting
		for command completion.

		Latency:
		There should be no increase in latency since the interrupt-thread has a
		high priority and will be run before an average task in user land
		(except the user changed priorities).

Documentation/usb/power-management.txt

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		@@ -487,3 +487,29 @@ succeed, it may still remain active and thus cause the system to
		resume as soon as the system suspend is complete. Or the remote
		wakeup may fail and get lost. Which outcome occurs depends on timing
		and on the hardware and firmware design.


		xHCI hardware link PM
		---------------------

		xHCI host controller provides hardware link power management to usb2.0
		(xHCI 1.0 feature) and usb3.0 devices which support link PM. By
		enabling hardware LPM, the host can automatically put the device into
		lower power state(L1 for usb2.0 devices, or U1/U2 for usb3.0 devices),
		which state device can enter and resume very quickly.

		The user interface for controlling USB2 hardware LPM is located in the
		power/ subdirectory of each USB device's sysfs directory, that is, in
		/sys/bus/usb/devices/.../power/ where "..." is the device's ID. The
		relevant attribute files is usb2_hardware_lpm.

		power/usb2_hardware_lpm

		When a USB2 device which support LPM is plugged to a
		xHCI host root hub which support software LPM, the
		host will run a software LPM test for it; if the device
		enters L1 state and resume successfully and the host
		supports USB2 hardware LPM, this file will show up and
		driver will enable hardware LPM for the device. You
		can write y/Y/1 or n/N/0 to the file to enable/disable
		USB2 hardware LPM manually. This is for test purpose mainly.

MAINTAINERS

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		@@ -2136,6 +2136,14 @@ M: Matthew Garrett <mjg59@srcf.ucam.org>
		S: Maintained
		F: drivers/platform/x86/dell-wmi.c

		DESIGNWARE USB3 DRD IP DRIVER
		M: Felipe Balbi <balbi@ti.com>
		L: linux-usb@vger.kernel.org
		L: linux-omap@vger.kernel.org
		T: git git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb.git
		S: Maintained
		F: drivers/usb/dwc3/

		DEVICE NUMBER REGISTRY
		M: Torben Mathiasen <device@lanana.org>
		W: http://lanana.org/docs/device-list/index.html

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