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authorHans Verkuil <hverkuil@xs4all.nl>2014-07-26 13:02:59 -0300
committerMauro Carvalho Chehab <m.chehab@samsung.com>2014-07-27 17:51:37 -0300
commit9c9cb1fad865b3d9e9c4d7bbfbd20ca04cdc79b3 (patch)
treea5c73516fb21deb7d7fc60dd7d841d2900d106bc /drivers
parent5b8c8d41919ac4985dfacd31a860e4f00f52d3a6 (diff)
[media] v4l2-ctrls: fix rounding calculation
Commit 958c7c7e65 ("[media] v4l2-ctrls: fix corner case in round-to-range code") broke controls that use a negative range. The cause was a s32/u32 mixup: ctrl->step is unsigned while all others are signed. So the result type of the expression '(ctrl)->maximum - ((ctrl)->step / 2)' became unsigned, making 'val >= (ctrl)->maximum - ((ctrl)->step / 2)' true, since '((u32)-128) > 128' (if val = -128, maximum = 128 and step = 1). So carefully cast (step / 2) to s32. There was one cast of step to s32 where it should have been u32 because both offset and step are unsigned, so casting to signed makes no sense there. You do need a cast to u32 there, because otherwise architectures that have no 64-bit division start complaining (step is a u64). Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Reported-by: Frank Schäfer <fschaefer.oss@googlemail.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/media/v4l2-core/v4l2-ctrls.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 2d8ced8ad80b..f030d6a9e044 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1347,14 +1347,14 @@ static void std_log(const struct v4l2_ctrl *ctrl)
({ \
offset_type offset; \
if ((ctrl)->maximum >= 0 && \
- val >= (ctrl)->maximum - ((ctrl)->step / 2)) \
+ val >= (ctrl)->maximum - (s32)((ctrl)->step / 2)) \
val = (ctrl)->maximum; \
else \
- val += (ctrl)->step / 2; \
+ val += (s32)((ctrl)->step / 2); \
val = clamp_t(typeof(val), val, \
(ctrl)->minimum, (ctrl)->maximum); \
offset = (val) - (ctrl)->minimum; \
- offset = (ctrl)->step * (offset / (s32)(ctrl)->step); \
+ offset = (ctrl)->step * (offset / (u32)(ctrl)->step); \
val = (ctrl)->minimum + offset; \
0; \
})
@@ -1376,10 +1376,10 @@ static int std_validate(const struct v4l2_ctrl *ctrl, u32 idx,
* the u64 divide that needs special care.
*/
val = ptr.p_s64[idx];
- if (ctrl->maximum >= 0 && val >= ctrl->maximum - ctrl->step / 2)
+ if (ctrl->maximum >= 0 && val >= ctrl->maximum - (s64)(ctrl->step / 2))
val = ctrl->maximum;
else
- val += ctrl->step / 2;
+ val += (s64)(ctrl->step / 2);
val = clamp_t(s64, val, ctrl->minimum, ctrl->maximum);
offset = val - ctrl->minimum;
do_div(offset, ctrl->step);

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