The intermediate calculation in the expression for hblank can exceed
32 bit signed range. This overflow can lead to negative values for
hblank. Typecasting intermediate variable to higher precision.
Cc: Hans Verkuil <hans.verk...@cisco.com>
Cc: Martin Bugge <marbu...@cisco.com>
Signed-off-by: Prashant Laddha <prlad...@cisco.com>
---
drivers/media/v4l2-core/v4l2-dv-timings.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-dv-timings.c
b/drivers/media/v4l2-core/v4l2-dv-timings.c
index 86e11d1..9d27f05 100644
--- a/drivers/media/v4l2-core/v4l2-dv-timings.c
+++ b/drivers/media/v4l2-core/v4l2-dv-timings.c
@@ -573,15 +573,15 @@ bool v4l2_detect_gtf(unsigned frame_height,
/* Horizontal */
if (default_gtf)
- h_blank = ((image_width * GTF_D_C_PRIME * hfreq) -
- (image_width * GTF_D_M_PRIME * 1000) +
- (hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000)
/ 2) /
- (hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000);
+ h_blank = ((image_width * GTF_D_C_PRIME * (long long)hfreq) -
+ ((long long)image_width * GTF_D_M_PRIME * 1000) +
+ ((long long)hfreq * (100 - GTF_D_C_PRIME) +
GTF_D_M_PRIME * 1000) / 2) /
+ ((long long)hfreq * (100 - GTF_D_C_PRIME) +
GTF_D_M_PRIME * 1000);
else
- h_blank = ((image_width * GTF_S_C_PRIME * hfreq) -
- (image_width * GTF_S_M_PRIME * 1000) +
- (hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000)
/ 2) /
- (hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000);
+ h_blank = ((image_width * GTF_S_C_PRIME * (long long)hfreq) -
+ ((long long)image_width * GTF_S_M_PRIME * 1000) +
+ ((long long)hfreq * (100 - GTF_S_C_PRIME) +
GTF_S_M_PRIME * 1000) / 2) /
+ ((long long)hfreq * (100 - GTF_S_C_PRIME) +
GTF_S_M_PRIME * 1000);
h_blank = ((h_blank + GTF_CELL_GRAN) / (2 * GTF_CELL_GRAN)) *
(2 * GTF_CELL_GRAN);
--
1.9.1
--
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