On Sat, 25 Jun 2011, Robert Jarzmik wrote: > On 06/22/2011 05:19 PM, Felipe Balbi wrote: > > Hi, > > > > On Wed, Jun 22, 2011 at 11:02:27AM -0400, Alan Stern wrote: > >> No, the patch is appropriate. > Indeed. > >> > >> We don't need better communication. If g_mass_storage (for example) > >> knows that the device is in use, it can block suspends by returning > >> -EBUSY from its own suspend callback. The UDC driver doesn't need to > >> worry about these matters; it should assume that such things have > >> already been handled elsewhere. That's what Dmitry meant when he was > >> talking about a "higher level driver" -- maybe "lower level" would have > >> been a better choice of words. :-) > The suspend at driver level should not care about filesystem in use, etc > ... A disconnected cable cannot be prevented by the kernel, and the > effect in fine is the same as the suspend. This is a little ironic, because the mass-storage gadget driver has no idea whether a filesystem is in use or not. All it knows is whether it is currently connected to a host. Besides, it's questionable whether the gadget driver should prevent the gadget from suspending. This is a policy matter which must be decided by the user, not by the kernel. Nevertheless... The fact that the kernel can do nothing about a disconnected cable shouldn't stop us from handling system sleep correctly. After all, the kernel _can_ do something about that. 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
