Ok, let's step back a bit here. Tianyu, I think you're confused about what exactly USB device suspend is, and what remote wakeup is. I suggest you read Documentation/power-management.txt.
I think Tianyu is concerned that the port power off mechanism will not be used very often because many USB devices are suspended with remote wakeup on. That is a fact of life, and adding new sysfs files will not help with that. Take a USB keyboard, for instance. If you turn on auto-suspend by echoing "auto" to power/control, the keyboard will suspend after no keystrokes are transmitted for two seconds. The usbhid driver suspends the keyboard with remote wakeup enabled. Then when the user presses a key, the keyboard sends remote wakeup signaling, and the usbhid driver sends a request to get the keystoke. If you attempt to disable remote wakeup, the keyboard will never send a wakeup when a key is pressed. To the user, the keyboard is "broken". Several USB drivers that need remote wakeup work this way. USB 3G modems, for example, need to send a remote wakeup signal when someone receives a text message. This is just the way USB devices are designed. We will just have to accept that the port power off mechanism won't be used with these USB devices. Sarah Sharp -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
