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USB 2.0 LPM ecn RRS feed

Answers

  • Windows 8 has limited support for it. If a LPM capable device is attached directly to a XHCI controller that advertises support for hardware LPM, we will program the controller to initiate L1 transitions automatically. We do not initiate a L1 transition in the driver stack.

    Thursday, November 15, 2012 5:54 PM

All replies

  • Windows 8 has limited support for it. If a LPM capable device is attached directly to a XHCI controller that advertises support for hardware LPM, we will program the controller to initiate L1 transitions automatically. We do not initiate a L1 transition in the driver stack.

    Thursday, November 15, 2012 5:54 PM
  • Thanks for your reply
    Friday, November 16, 2012 1:15 AM
  • If I plug the USB 2.0 deivce(support HW LPM) into USB 3.0 port, it should still work with EHCI controller. So it means....Win8 will not support LPM L1 for USB 2.0 device. Is it correct ?
    Friday, November 16, 2012 1:53 AM
  • is the following description correct?

    If the U2 device is plugged into the XHCI port, then LPM L1 is supported by HW. 

    If the U2 device is plugged into a non-XHCI, it will not enable LPM L1 (Controller driver does not support)

    Monday, November 19, 2012 2:40 PM
  • Yes, we do not support L1 for non-XHCI controllers.

    Tuesday, November 20, 2012 6:03 PM