drm: Fix drm_fixp2int_round() making it add 0.5

[ Upstream commit 807f96abdf ]

As well noted by Pekka[1], the rounding of drm_fixp2int_round is wrong.
To round a number, you need to add 0.5 to the number and floor that,
drm_fixp2int_round() is adding 0.0000076. Make it add 0.5.

[1]: https://lore.kernel.org/all/20240301135327.22efe0dd.pekka.paalanen@collabora.com/

Fixes: 8b25320887 ("drm: Add fixed-point helper to get rounded integer values")
Suggested-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Arthur Grillo <arthurgrillo@riseup.net>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240316-drm_fixed-v2-1-c1bc2665b5ed@riseup.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Arthur Grillo 2024-03-16 13:25:20 -03:00 committed by Sasha Levin
parent 68fb3d6e17
commit be300fb44a

View File

@ -71,7 +71,6 @@ static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B)
}
#define DRM_FIXED_POINT 32
#define DRM_FIXED_POINT_HALF 16
#define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT)
#define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1)
#define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK)
@ -90,7 +89,7 @@ static inline int drm_fixp2int(s64 a)
static inline int drm_fixp2int_round(s64 a)
{
return drm_fixp2int(a + (1 << (DRM_FIXED_POINT_HALF - 1)));
return drm_fixp2int(a + DRM_FIXED_ONE / 2);
}
static inline int drm_fixp2int_ceil(s64 a)