redonkable/alistair23-linux
redonkable/alistair23-linux
1
0
Fork 0
Code Releases Activity

[media] v4l2-dv-timing: avoid rounding twice in gtf hblank calc

Browse source 
Currently, in gtf hblank calculations, the rounding is used twice,
one at intermediate division and one at final state where hblank
is rounded to nearest multiple of twice cell granularity. This
error got introduced in 'commit d7ed5a3dda ("[media]
v4l2-dv-timings: fix rounding in hblank and hsync calculation"),
where it missed combining the rounding step. Correcting the same
in this patch.

Signed-off-by: Prashant Laddha <prladdha@cisco.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
This commit is contained in:
Prashant Laddha 2015-06-05 05:13:31 -03:00 committed by Mauro Carvalho Chehab
parent 7a5d99e7c9
commit dc0cf4cfed
1 changed files with 6 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
drivers/media/v4l2-core/v4l2-dv-timings.c
View file

@ -561,20 +561,22 @@ bool v4l2_detect_gtf(unsigned frame_height,
num = ((image_width * GTF_D_C_PRIME * (u64)hfreq) -
((u64)image_width * GTF_D_M_PRIME * 1000));
den = hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000;
den = (hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000) *
(2 * GTF_CELL_GRAN);
h_blank = div_u64((num + (den >> 1)), den);
h_blank *= (2 * GTF_CELL_GRAN);
} else {
u64 num;
u32 den;
num = ((image_width * GTF_S_C_PRIME * (u64)hfreq) -
((u64)image_width * GTF_S_M_PRIME * 1000));
den = hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000;
den = (hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000) *
(2 * GTF_CELL_GRAN);
h_blank = div_u64((num + (den >> 1)), den);
h_blank *= (2 * GTF_CELL_GRAN);
}
h_blank = ((h_blank + GTF_CELL_GRAN) / (2 * GTF_CELL_GRAN)) *
(2 * GTF_CELL_GRAN);
frame_width = image_width + h_blank;
pix_clk = (image_width + h_blank) * hfreq;