On Wed, 9 Feb 2011, Sarah Sharp wrote: > I've been testing a 3G modem that uses the option driver in 2.6.37, and > we noticed that the device wasn't going into autosuspend. Upon further > investigation, we found that remote wakeup is disabled by default, and > the option driver will only suspend the device between transmissions if > remote wakeup is enabled by userspace. No, you have misunderstood. Autosuspend fails if the device _doesn't support_ remote wakeup -- this has nothing to do with the user's setting of the power/wakeup attribute. Also, I'm not sure what you mean by "between transmissions". The option driver requires remote wakeup while the device file is open but not while the file is closed. Hence there should be nothing preventing autosuspend when the device is not in use. > Is there a reason remote wakeup is disabled by default? The power/wakeup attribute applies to system sleep (suspend or hibernation), not runtime suspend. It is supposed to be disabled by default for all devices except those normally expected to wake up a sleeping computer (power button, lid, keyboard, maybe network interface). It is not enabled by default for USB hubs, for example, even though all hubs support remote wakeup. Otherwise your sleeping laptop would wake up the moment you unplugged the USB mouse. > Is there a > history of devices that use the option driver having issues with > auto-suspend? It seems like if the USB device advertises remote wakeup > and the device is self-powered, then we should turn on remote wakeup by > default. This question doesn't mean what you think it means. Besides, are you really sure the device advertises remote wakeup capability? Can you post the "lsusb -v" output for the modem? Alan Stern -- 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
