On Fri, 2013-11-22 at 01:08 -0800, Dan Williams wrote: > From: Lan Tianyu <tianyu.lan@xxxxxxxxx> > > Describe the mechanisms for controlling port power policy and > discovering the port power state. > + power/pm_qos_no_power_off: > + This writable flag is a global enable / disable for port > + power management. Once this file is set to '0' poweroff > + may occur once all other constraints are met. This > + defaults to '1'. > + > + power/control: > + This file is writable and can be set to > + 'auto' (the default) to let the kernel power down the > + device when it is idle, or 'on' to disable power > + management and keep the port powered. These entries contradict one another. I think you need to rewrite them. > + connect_type: > + This writable file reflects the capability of the > + connection to respond to hotplug events. It returns one > + of four values 'hotplug', 'hardwired', 'not used', and > + 'unknown'. The default value is populated by platform > + firmware, and for all but the 'hardwired' type hotplug > + support is enabled. One can write 'hardwired' to turn > + off hotplug (allow the port to power down), or 'hotplug' > + to keep the port powered. The other types can not be > + written to the file. > + > + Details on the connection type: > + "hotplug" refers to a port on the outside of a laptop > + which is visible and connectable. > + > + "hardwired" refers to a port that is not visible but > + connectable. Examples are internal ports for USB > + bluetooth that can be disconnected via an external > + switch or a port with a hardwired USB camera. But those are different cases. The bluetooth module will react to rfkill with a hotplug. The camera won't. The examples are poorly chosen. > + > + "not used" refers to internal port that will never have > + a device connected to it. These may be empty internal > + ports, or ports that are not physically > + exposed on a platform. > + > + "unknown" means platform does not provide information > + for this port. Regards Oliver -- 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
