| Message ID | 20170228211453.3688400-1-arnd@arndb.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Feb 28, 2017 at 10:14:37PM +0100, Arnd Bergmann wrote: > tw5864_frameinterval_get() only initializes its output when it successfully > identifies the video standard in tw5864_input. We get a warning here because > gcc can't always track the state if initialized warnings across a WARN() > macro, and thinks it might get used incorrectly in tw5864_s_parm: > > media/pci/tw5864/tw5864-video.c: In function 'tw5864_s_parm': > media/pci/tw5864/tw5864-video.c:816:38: error: 'time_base.numerator' may be used uninitialized in this function [-Werror=maybe-uninitialized] > media/pci/tw5864/tw5864-video.c:819:31: error: 'time_base.denominator' may be used uninitialized in this function [-Werror=maybe-uninitialized] > > Using dev_warn() instead of WARN() avoids the __branch_check__() in > unlikely and lets the compiler see that the initialization is correct. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Thanks for the patch. Acked-by: Andrey Utkin <andrey.utkin@corp.bluecherry.net> See the note below. > --- > drivers/media/pci/tw5864/tw5864-video.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/media/pci/tw5864/tw5864-video.c b/drivers/media/pci/tw5864/tw5864-video.c > index 9421216bb942..4d9994a11c22 100644 > --- a/drivers/media/pci/tw5864/tw5864-video.c > +++ b/drivers/media/pci/tw5864/tw5864-video.c > @@ -717,6 +717,8 @@ static void tw5864_frame_interval_set(struct tw5864_input *input) > static int tw5864_frameinterval_get(struct tw5864_input *input, > struct v4l2_fract *frameinterval) > { > + struct tw5864_dev *dev = input->root; > + > switch (input->std) { > case STD_NTSC: > frameinterval->numerator = 1001; > @@ -728,8 +730,8 @@ static int tw5864_frameinterval_get(struct tw5864_input *input, > frameinterval->denominator = 25; > break; > default: > - WARN(1, "tw5864_frameinterval_get requested for unknown std %d\n", > - input->std); > + dev_warn(&dev->pci->dev, "tw5864_frameinterval_get requested for unknown std %d\n", > + input->std); > return -EINVAL; > } Looks good, though, arguably, it could fit 80 columns better if you put the string literal to separate line.
diff --git a/drivers/media/pci/tw5864/tw5864-video.c b/drivers/media/pci/tw5864/tw5864-video.c index 9421216bb942..4d9994a11c22 100644 --- a/drivers/media/pci/tw5864/tw5864-video.c +++ b/drivers/media/pci/tw5864/tw5864-video.c @@ -717,6 +717,8 @@ static void tw5864_frame_interval_set(struct tw5864_input *input) static int tw5864_frameinterval_get(struct tw5864_input *input, struct v4l2_fract *frameinterval) { + struct tw5864_dev *dev = input->root; + switch (input->std) { case STD_NTSC: frameinterval->numerator = 1001; @@ -728,8 +730,8 @@ static int tw5864_frameinterval_get(struct tw5864_input *input, frameinterval->denominator = 25; break; default: - WARN(1, "tw5864_frameinterval_get requested for unknown std %d\n", - input->std); + dev_warn(&dev->pci->dev, "tw5864_frameinterval_get requested for unknown std %d\n", + input->std); return -EINVAL; }
tw5864_frameinterval_get() only initializes its output when it successfully identifies the video standard in tw5864_input. We get a warning here because gcc can't always track the state if initialized warnings across a WARN() macro, and thinks it might get used incorrectly in tw5864_s_parm: media/pci/tw5864/tw5864-video.c: In function 'tw5864_s_parm': media/pci/tw5864/tw5864-video.c:816:38: error: 'time_base.numerator' may be used uninitialized in this function [-Werror=maybe-uninitialized] media/pci/tw5864/tw5864-video.c:819:31: error: 'time_base.denominator' may be used uninitialized in this function [-Werror=maybe-uninitialized] Using dev_warn() instead of WARN() avoids the __branch_check__() in unlikely and lets the compiler see that the initialization is correct. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/media/pci/tw5864/tw5864-video.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)