drivers/media/usb/dvb-usb-v2/dvb_usb_core.c: In function 'dvb_usbv2_media_device_register':
drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:433:2: warning: ignoring return value of '__media_device_register', declared with attribute warn_unused_result [-Wunused-result]
media_device_register(adap->dvb_adap.mdev);
^
drivers/media/usb/dvb-usb/dvb-usb-dvb.c: In function 'dvb_usb_media_device_register':
drivers/media/usb/dvb-usb/dvb-usb-dvb.c:128:2: warning: ignoring return value of '__media_device_register', declared with attribute warn_unused_result [-Wunused-result]
media_device_register(adap->dvb_adap.mdev);
^
Those are because the drivers are not properly checking if the
media device init and register were succeeded.