Messages in this thread | | | Date | Wed, 10 Jun 2020 10:32:20 -0400 | From | Alan Stern <> | Subject | Re: [PATCH 1/2] xhci: Suspend ports to U3 directly from U1 or U2 |
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On Wed, Jun 10, 2020 at 02:42:30PM +0800, Kai-Heng Feng wrote: > xHCI spec "4.15.1 Port Suspend" states that port can be put to U3 as long > as Enabled bit is set and from U0, U1 or U2 state. > > Currently only USB_PORT_FEAT_LINK_STATE puts port to U3 directly, let's > do the same for USB_PORT_FEAT_SUSPEND and bus suspend case. > > This is particularly useful for USB2 devices, which may take a very long > time to switch USB2 LPM on and off.
Have these two patches been tested with a variety of USB-2.0 and USB-2.1 devices?
Alan Stern
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