ok, thanks. :-) gchen. 于 2012年12月07日 23:18, Alan Stern 写道: > 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 > > > -- Chen Gang Asianux Corporation -- 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
