On Fri, 16 Sep 2011, Greg KH wrote: > > Following the kernel's policy, USB host controllers currently are > > disabled for remote wakeup by default. This really isn't what we should > > do. If the user wants a USB device to wake the system then he has to > > "echo enabled >/sys/.../power/wakeup" for both the device and its > > controller. There's no reason to require that second step -- we lose > > nothing by enabling wakeups on the controller by default. > > > > What do people think about this change in the policy? > > It makes sense to change this by default, but what does that mean for > existing users? Will their systems suddenly wakeup when previously they > didn't? As far as I can tell, the only USB devices currently enabled for remote wakeup by default are keyboards and root hubs. My proposed patch would disable root hubs and enable host controllers. As a result, the only change people should see is that (unless they or their distributions deliberately alter the settings) pressing a key on a USB keyboard will wake up a sleeping system whereas before it would not. It's hard to say whether this is good or bad. I don't normally use a USB keyboard, and my systems _do_ wake up when I press a key, which I regard as desirable. The proposed change would make USB keyboards behave the same as my PS/2 and laptop keyboards. Other people might not feel the same way about it, though. As for other subsystems, I can't say much. Changing the policy doesn't have any immediate effect, of course -- people still have to change the code. But I think it makes sense. Even for something simple like PCI bridges; we obviously want bridges to forward PME# signals to the CPU. 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
