I have another question about USB selective-suspend function with multipe USB device. -------------------------------------------------------------------- Environment: HP Pavillion dm3 Processor: Genuine Intel(R) CPU U2300 @1.20GHz RAM: 4.0 GB OS: Win 7 home premium, x32/x64 build 7264 or 7600 USB chipset: Intel(R) ICH9 Family USB2 Enhanced Host controller - 293A/293C ============================================================================== Use any two external WebCams with in-box driver (have selective suspend function) in the same root hub, After they enter selective suspend state, unplug one WebCam, Sometimes another WebCam can't work well. (WebCam's USB bus is abnormal. No any SOF) (WebCam's USB bus is abnormal. No any SOF) Use CATC to capture USB bus, can find abnormal singals, Full speed J (suspend), Full speed K (resume), SOF, SOF, ...., Full speed J. (2.1 ms) (65.5 ms) (4.2 us) Normal singals: Full speed J (suspend), Full speed K (resume), SOF, SOF, ...., Full speed J (suspend), Full speed K (resume), ........ (2.1 ms) (62.9 ms) (6.8 ms) (68.2) We found a document about this (Microsoft knowledge base article ID: 968132 http://support.microsoft.com/?scid=kb%3Ben-us%3B968132&x=8&y=10 Dose Win 7 solve this issue ? (multiple devices connected to the same USB hub go into selective suspend) It seems no problem in AMD platform (different south-bridge and USB chipset). I try to disable save power function of the USB root hub in the device management. It works well for the same test follow. Use CATC to capture the USB bus. (After unplug one webcam, capture antoher webcam's USB bus) it only appear a pair of "Full speed J" and "Full speed K" Full speed J (suspend), Full speed K (resume), SOF, SOF ........ (2.1 ms) (76.6 ms)