Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH] [media] tw5864: handle unknown video std gracefully | Date | Mon, 27 Feb 2017 21:32:34 +0100 |
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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]
This particular use happens to be ok, but we do copy the uninitialized output of tw5864_frameinterval_get() into other memory without checking the return code, interestingly without getting a warning here.
This initializes the output to 1/1s for the case, to make sure we do get an intialization that doesn't cause a division-by-zero exception in case we end up using this uninitialized data later.
This also avoids the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/media/pci/tw5864/tw5864-video.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/media/pci/tw5864/tw5864-video.c b/drivers/media/pci/tw5864/tw5864-video.c index 9421216bb942..a451c2081fde 100644 --- a/drivers/media/pci/tw5864/tw5864-video.c +++ b/drivers/media/pci/tw5864/tw5864-video.c @@ -728,6 +728,8 @@ static int tw5864_frameinterval_get(struct tw5864_input *input, frameinterval->denominator = 25; break; default: + frameinterval->numerator = 1; + frameinterval->denominator = 1; WARN(1, "tw5864_frameinterval_get requested for unknown std %d\n", input->std); return -EINVAL; -- 2.9.0
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