[PATCH] [media] tw5864: use dev_warn instead of WARN to shut up warning

From: Arnd Bergmann
Date: Tue Feb 28 2017 - 16:19:05 EST


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@xxxxxxxx>
---
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;
}

--
2.9.0