On Fri, Jun 17, 2011 at 2:44 PM, suman <vijayendra.suman@xxxxxxxxx> wrote: > Hi Amit, > > How is the USB connected in your system Is it through some USB > controller, or directly to some CPU GPIO pins, you can program CPU > registers to power down but you need to check the CPU spec, this in > effect will bring the power down. If it is connected through some USB > controller you can check the Spec, they have such commands to power > down the controller. > currently i am referring to EHCI specs rev 1.0 Section 4.2.4 "Port Power " and Table 4-3 , it says : "The Port Power Control (PPC) bit in the HCSPARAMS register indicates whether the USB 2.0 host controller has port power control (See Section 2.2.3). When this bit is a zero, then the host controller does not support software control of port power switches. When in this configuration, the port power is always available and the companion host controllers must implement functionality consistent with port power always on. When the PPC bit is a one, then the host controller implementation includes port power switches. Each available switch has an output enable, which is referred to in this discussion as PortPowerOutputEnable (PPE). PPE is controlled based on the state of the combination bits PPC bit, EHCI Configured (CF)-bit and individual Port Power (PP) bits . Table 4–3 illustrates the summary behavioral model. " can this be used to achieve poweroff / on usb port ? Regards Amit Nagal -- 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
