On Fri, 7 Dec 2012, Chen Gang wrote: > but I still not quite be sure, please help checking (total 3 steps, below). > > thanks. > > ------------------------------------------------------------------------------ > Step 1: > > in drivers/usb/core/sysfs.c: > > for the same device, can usb_dev_authorized_store be called multi-times ? > according to the function comments, it seems can be called multi-times. Yes, it can. > Step 2: > > in drivers/usb/core/hub.c: > > usb_authorize_device may call usb_enumerate_device at line 2355 Yes. > Step 3: > > also in drivers/usb/core/hub.c: > > if udev->config != NULL: > we will assume that it has already configured, > and will not call usb_get_configuration again. > > if first call for usb_get_confiuration failed, may udev->config will not be NULL. > and next call usb_enumerate_device, > we will misunderstand that it has already configured (all things are 0). If the first call to usb_get_configuration fails, there won't be any more calls to usb_enumerate_device. The device will be rejected by usb_new_device. 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
