On Wed, May 21, 2014 at 1:29 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Tue, 20 May 2014, Dan Williams wrote: > >> From: Lan Tianyu <tianyu.lan@xxxxxxxxx> >> >> describe the mechanisms for controlling port power policy and >> discovering the port power state. > > >> +Example of the relevant files for port power control. >> + >> + child device link + >> + port device + | >> + parent hub + | | >> + v v v >> + /sys/bus/devices/usb2/2-0:1.0/port1/device >> + >> + /sys/bus/devices/usb2/2-0:1.0/port1/power/pm_qos_no_power_off >> + /sys/bus/devices/usb2/2-0:1.0/port1/device/power/control >> + /sys/bus/devices/usb2/2-0:1.0/port1/device/2-1:<intf0>/driver/unbind >> + /sys/bus/devices/usb2/2-0:1.0/port1/device/2-1:<intf1>/driver/unbind >> + ... >> + /sys/bus/devices/usb2/2-0:1.0/port1/device/2-1:<intfN>/driver/unbind > > These port names are out of date. Likewise the names below. Fixed. > > +While a superspeed port is powered off a device may downgrade its > +connection and attempt to connect to the hi-speed pins. The > +implementation takes steps to prevent this: > + > +1/ Port suspend is sequenced to guarantee that hi-speed ports are powered-off > + before their superspeed peer is permitted to power-off. The implication is > + that the setting pm_qos_no_power_off to zero on a superspeed port may not cause > + the port to power-off until its highspeed peer to go to its runtime suspend > > s/to go/has gone/ Fixed. Thanks, Alan! -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
