The hole reason for __must_check is to not ignore an error. However, a "ret" value is used at cx25821 just to avoid the Kernel compilation to compain about it. That, however, produces another warning (with W=1): drivers/media/pci/cx25821/cx25821-alsa.c: In function 'cx25821_audio_fini': drivers/media/pci/cx25821/cx25821-alsa.c:727:6: warning: variable 'ret' set but not used [-Wunused-but-set-variable] With the current implementation of driver_for_each_device() and cx25821_alsa_exit_callback(), there's actually just one very unlikely condition where it will currently produce an error: if driver_find() returns NULL. Ok, there's not much that can be done, as it is on a driver's function that returns void, but it can at least print some message if the error happens. Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> --- drivers/media/pci/cx25821/cx25821-alsa.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/media/pci/cx25821/cx25821-alsa.c b/drivers/media/pci/cx25821/cx25821-alsa.c index 81361c2..6e91e84 100644 --- a/drivers/media/pci/cx25821/cx25821-alsa.c +++ b/drivers/media/pci/cx25821/cx25821-alsa.c @@ -727,6 +727,8 @@ static void cx25821_audio_fini(void) int ret; ret = driver_for_each_device(drv, NULL, NULL, cx25821_alsa_exit_callback); + if (ret) + pr_err("%s failed to find a cx25821 driver.\n", __func__); } static int cx25821_alsa_init_callback(struct device *dev, void *data) -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html