On Saturday 06 March 2010, Alan Stern wrote: > On Fri, 5 Mar 2010, Rafael J. Wysocki wrote: > > > > So the problem is that subsystems can't usefully set the can_wakeup > > > flag before doing either device_initialize() or device_register(). > > > This can be fixed easily by removing the call in device_initialize(). > > > > PCI depends on the flag being unset when pci_pm_init(dev) is called. > > > > If that's still valid after removing the call in device_initialize(), I'm fine > > with the removal. > > It should still be valid. After all, there's nothing else to set the > flag except for other parts of the PCI core. All right, then. > > > Agreed, ethtool and sysfs should affect the same flags. > > > > Yeah, but. Right now, if the setting is changed via sysfs, it doesn't modify > > the WoL setting as visible by ethtool. > > > > I don't understand. Do you mean there's no way to update the > > > _device's_ WoL setting when the sysfs attribute is changed? > > > > There's no code for that, that's the problem. > > > > > The device's WoL setting matters only at suspend time. So the network > > > driver's suspend routine ought to test device_may_wakeup() to see > > > whether or not WoL should be enabled. Maybe this can be centralized > > > somewhere in the network stack. > > > > Maybe. The problem is people expect wakeup to work once WoL has been set > > with the help of ethtool and they expect it to work if the WoL is set by > > default. > > It's not difficult in theory to tie together the WoL setting and the > wakeup flag: > > If ethtool changes the WoL setting, the driver's ioctl handler > should make the corresponding change to the wakeup flag. > > If ethtool queries the WoL setting, the ioctl handler should > check the wakeup flag. If the flag is off, it should report > that WoL is disabled; if the flag is on, it should report that > WoL is enabled. (The same check should be made in the suspend > routine.) That's done this way already in all drivers I know, but we need a hook from wake_store() back to the driver. > > > And also IMO, enabling WoL by default is very questionable. But that's > > > a separate matter. > > > > That's been a common practice for years in the network adapter land and I don't > > think we're able to change that now. Besides, if the WoL is set to g by > > default, which also is common, that doesn't really lead to any problems. > > All right, we can declare that network drivers are allowed to enable > WoL by default (like keyboard drivers). There shouldn't be any problem > provided they initialize the wakeup setting before registering the > network interface, so that the initialization doesn't override any > action by udev. That sounds reasonable. Rafael -- 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
