On 03/13, Arthur Grillo wrote: > > > On 12/03/24 15:27, Melissa Wen wrote: > > On 03/06, Arthur Grillo wrote: > >> 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@xxxxxxxxxxxxx/ > >> > > Hi Arthur, > > > > thanks for addressing this issue. > > > > Please, add a fix tag to the commit that you are fixing, so we can > > easily backport. Might be this commit: > > https://cgit.freedesktop.org/drm/drm-misc/commit/drivers/gpu/drm/vkms?id=ab87f558dcfb2562c3497e89600dec798a446665 > >> Suggested-by: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxx> > >> Signed-off-by: Arthur Grillo <arthurgrillo@xxxxxxxxxx> > >> --- > >> include/drm/drm_fixed.h | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h > >> index 0c9f917a4d4b..de3a79909ac9 100644 > >> --- a/include/drm/drm_fixed.h > >> +++ b/include/drm/drm_fixed.h > >> @@ -90,7 +90,7 @@ 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))); > > Also, this is the only usage of DRM_FIXED_POINT_HALF. Can you also > > remove it as it won't be used anymore? > > > >> + return drm_fixp2int(a + DRM_FIXED_ONE / 2); > > Would this division be equivalent to just shifting 1ULL by 31 instead of > > 32 as done in DRM_FIXED_ONE? > > Yes, but I think the division makes it easier to understand what is > going on. Right. I was thinking about slightly better performance, but I don't have any data. We can go with this since you consider more readable, anyway. Can you send another version addressing the other comments? Then I can cherry-pick and already apply the fix. Thanks, Melissa > > Best Regards, > ~Arthur Grillo > > > > > Melissa > > > >> } > >> > >> static inline int drm_fixp2int_ceil(s64 a) > >> > >> -- > >> 2.43.0 > >>
