USB port power off Kernel/Userspace API - Sarah Sharp

Registered by Paul McKenney on 2012-05-23

[Slides](http://dl.dropbox.com/u/96820575/sarah-sharp-lpt-port-power-off2-mini.pdf)

The Intel Lynx Point chipset includes a new power savings mechanism that allows software to turn off the USB port power (VBUS) via an ACPI call. This mechanism is designed to save power on unused internal USB ports, but it could be used to save power on external ports or even simulate a physical disconnect for misbehaving USB devices. This presentation will provide background on the mechanism, before opening the floor to discussion on what sort of API the kernel should provide userspace to power down ports, and how userspace could use this API to save power, while not confusing the user with "dead" USB ports. Target audience: kernel developers working with USB device drivers, userspace developers for applications that touch USB devices (e.g. libusb, ModemManager, ConnMan), and desktop developers for Gnome, KDE, XFCE, etc.

Sarah Sharp is the xHCI driver maintainer. She has been adding USB 3.0 support to the Linux kernel for the past five years. Sarah works in Intel's Open Source Technology Center, along with Tianyu Lan. Tianyu (<email address hidden>) is a Linux kernel ACPI developer, and is the author of the patchset for the port power off mechanism.

Blueprint information

Status:
Not started
Approver:
None
Priority:
Undefined
Drafter:
None
Direction:
Needs approval
Assignee:
LPC Submitter
Definition:
New
Series goal:
None
Implementation:
Unknown
Milestone target:
None

Related branches

Sprints

Whiteboard

(?)

Work Items

This blueprint contains Public information 
Everyone can see this information.

Subscribers

No subscribers.